JPH1098756A - Simplified portable telephone terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a communication disabled period and to actualize a smooth operation by more shortening the time from the start of a hand-over processing to the end of a switch-back processing. SOLUTION: During a telephone call, a control part 16 detects a radio reception level from another base station by using a slot other than the communication slot, and stores a memory 14 with identification information (CS-ID) on the base station which is sending out the signal of the radio reception level together with its radio reception level when the radio reception level exceeds a threshold level. Then when a shift to the hand-over processing is instructed from the current base station of the communication, the control part 16 performs the hand-over processing for the corresponding base station by referring to the (CS-ID) in the memory 14. If the (CS-ID) is not stored in the memory 14 at this time, a connection switch-back processing for the original base station is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a personal handy phone system (PHS) and a simplified portable telephone terminal for communicating with one of a plurality of base stations connected to a public network via a radio line. (Hereinafter referred to as PHS terminal)
More specifically, the present invention relates to an improvement in connection control when reconnecting to another adjacent base station from a base station in a call.

[0002]

2. Description of the Related Art As one of typical service functions of the PHS, a PHS terminal that is in communication with a certain base station in a public network is transmitted from the base station based on detection of radio reception level deterioration or reception quality deterioration. A reconnection (handover) processing function of reconnecting from the base station currently in communication to another base station by receiving the predetermined control information
At the time of the transition to the handover, a switchback processing function is known in which when there is no other connectable base station, the connection is restored to the connection to the base station which has been connected up to then.

[0003] As a specific process related to these service functions, when a PHS terminal receives the control information from a connected base station, the radio reception level is higher than a threshold level previously held by the PHS terminal. If there is a base station that performs, a handover process is performed, and if there is no base station whose radio reception level is equal to or higher than the threshold level,
Switching back to the original base station without handover is performed.

[0004] By the way, such handover processing is performed as follows.
It is also realized in a digital mobile phone system employing TDMA (Time Division Multiple Access). In the case of a mobile phone system, a TDM as shown in FIG.
An A frame is used, and has a timing (I) that is independent of transmission (T) and reception (R). This allows
The mobile station (mobile phone terminal) of the TDMA system has a timing (I) that is irrelevant to its own transmission / reception even during operation.
Since it is always present in the DMA frame, it is possible to monitor the carrier from the adjacent base station at this timing (I), and it is possible to cope with the handover process without interrupting the call based on the monitoring result.

[0005] On the other hand, the frame used in the PHS has a different standard from the TDMA frame, and basically has only transmission (T) and reception (R) timings. Therefore, the PHS terminal cannot assign timings other than its own transmission / reception, unlike the mobile phone terminal, to measure the reception electric field strength from the adjacent base station, and uses the slot in its own reception frame. There is no other way than to deal with it.

[0006] In order to cope with such a restriction, the conventional PHS terminal uses a slot in a received frame exclusively for a call in a call state, and then, when a base station instructs to shift to a handover, when the base station issues an instruction to shift to a handover. Is searched for another base station whose radio reception level is equal to or higher than the threshold level held by the terminal itself. According to this configuration, in order to start searching for an adjacent base station after a handover transition, it takes time to perform a process of detecting a handover destination, and the processing time of the handover process and the return process becomes longer by that much. As a result,
The time during which calls could not be made had to be long.

[0007]

As described above, the conventional P
Since the HS terminal searches for another base station having a radio reception level of a predetermined threshold level after starting the handover process, it takes time until the handover process and the return process are completed. As a result, the period until the call can be resumed has to be lengthened by that much, and there is a problem that smooth operation is hindered.

The present invention eliminates the above-mentioned problems, and requires less time from the start of the handover process to the end of the reverting process, thereby realizing a smooth operation by minimizing the period during which calls cannot be made. It is an object to provide a simple portable telephone terminal.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a function of performing reconnection processing from a connected base station to another base station which is connected to a base station connected to a public network by a radio line, and a reconnection processing. In a simplified portable telephone terminal having a function of performing a switching process for connecting to the original base station when there is no reconnectable base station after the start, during a call with the base station, other than a call slot used for the call A search means for receiving a signal from an adjacent base station using the slot and searching for a base station whose reception level is equal to or higher than a predetermined level, and storing base station information corresponding to the base station searched by the search means Storage means, at the time of transition to the reconnection processing, reconnection processing means for performing the reconnection processing to the base station corresponding to the base station information stored in the storage means, Upon transition, If the base station information to the serial storage means is not stored, the reconnection process is stopped, characterized by comprising a switching back processing unit performs the cutting processing returns.

Preferably, the reconnection processing means performs the reconnection processing in the order of a base station having a higher reception level when a plurality of base station information are stored in the storage means at the time of transition to the reconnection processing. It is characterized by performing.

[0011] The present invention also provides a function of performing reconnection processing from a connected base station to another base station, which is connected to a base station connected to a public network via a radio line, and reconnecting after transition to the reconnection processing. In a simplified portable telephone terminal having a function of performing a return process for connecting to an original base station when a possible base station does not exist, during a call with the base station, a slot other than a talk slot used for the call is changed to an adjacent base station. Slot timing control means for controlling reception of a signal from a station, adjacent base station specifying means for specifying a base station having a reception level of a signal received in a slot other than the communication slot which is equal to or higher than a predetermined level, and the reconnection Connection control means for performing the reconnection processing or the return processing based on the identification result of the base station by the adjacent base station identification means at the time of transition to processing. The features.

Preferably, the adjacent base station specifying means receives a signal from the adjacent base station using a slot other than the communication slot, and searches for a base station having the reception level equal to or higher than a predetermined level; Storage means for storing base station information corresponding to the base station searched by the search means, wherein the connection control means stores the base station information stored in the storage means at the time of transition to the reconnection processing. Reconnection processing means for performing the reconnection processing for the corresponding base station, upon transition to the reconnection processing, if the base station information is not stored in the storage means, stop the reconnection processing, And a return processing means for performing the return processing.

[0013] When a plurality of pieces of base station information are stored in the storage means at the time of transition to the reconnection processing, the reconnection processing means performs the reconnection processing in the order of a base station having a higher reception level. It is characterized by the following.

Further, the present invention provides a function of performing a reconnection process from a connected base station to another base station which is connected to a base station connected to a public network by a radio line, and reconnecting after starting the reconnection process. In a simplified portable telephone terminal having a function of performing a return process for connecting to an original base station when a possible base station does not exist, a transmission and reception frame composed of a plurality of slots is used as a frame unit. And a plurality of slots in the received frame are assigned to at least a control slot and a plurality of communication slots, and a call control means for performing a call using one of the plurality of communication slots during a call with the base station. During communication with the base station, slot timing control means for controlling reception of a signal from an adjacent base station using a communication slot not used for the communication, Storage means for storing information indicating an adjacent base station corresponding to a signal received under the control of the slot timing control means; and information for indicating an adjacent base station is stored in the storage means upon transition to the reconnection processing. If not, a reconnection processing unit for stopping the reconnection processing and performing the switchback processing is provided.

Preferably, the storage means stores information indicating an adjacent base station and information indicating a reception level of a signal from the adjacent base station, and the reconnection processing means stores a plurality of base station information in the storage means. Is stored, the reconnection processing is performed in the order of the base station having the higher reception level.

Further, the reconnection processing means requests connection to an adjacent base station stored in the storage means based on a switching instruction from a base station during a call.

[0017]

According to the present invention, a signal from an adjacent base station is received using a slot other than the talk slot used for the call in parallel with the talk with the connected base station so that the wireless reception level can be maintained at a predetermined level. An adjacent base station having a threshold level or higher is specified, and at the time of transition to handover, handover processing is performed on the base station that has already been specified. According to this control, at the time of transition to handover,
Since it is already specified whether or not there is another base station whose radio reception level is equal to or higher than the predetermined threshold level, the handover process or the return process can be started immediately based on the specified result. As a result, with respect to the time from the transition to the handover to the end of the switching process, the time corresponding to searching for another base station whose radio reception level is equal to or higher than a predetermined threshold level can be saved, and The call unavailable period can be reduced by minutes.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a system configuration of a PHS according to the present invention, in which a plurality of PHS base stations (CS) 20 are installed in an exchange 30 in a public network.
Are connected, and each of these base stations 20 is connected to a PHS terminal (PS) 10 via a wireless line.

FIG. 2 is a block diagram showing a functional configuration of the PHS terminal 10 shown in FIG. 1. The PHS terminal 10 comprises an antenna 11, a radio unit 12, a communication circuit 13, a memory 14, a dial input unit 15, and a control unit 16. Is done. This PHS
In the terminal 10, during a call with the base station 20 via the wireless unit 12 and the call circuit 13, another slot adjacent to the base station 20 during the call is used by using a slot different from the call slot used for the call. Radio waves from the base station 20 are received by the antenna 11 and the radio unit 12.

FIG. 3 shows a PHS base station 2 according to the present invention.
FIG. 2 is a configuration diagram of a slot in a wireless channel between a PHS terminal 0 and a PHS terminal 10; In the figure, the base station 20 and the PHS terminal 1
0 performs communication using the transmission frame (T) and the reception frame (R) as one frame unit. Four slots SL1, SL2, S in the received frame (R) of the PHS terminal 10.
Of L3 and SL4, SL1 is a control slot and receives a control signal. SL2 is a call slot used during a call. SL3 is a slot for searching for another base station used for receiving a radio wave from a base station 20 different from the base station 20 during a call. SL4 is an empty slot, but can also be used as a slot for searching for another base station, like SL3.

Using the other base station search slot SL3,
PHS terminal 10 that has received a radio wave from another base station 20
In, the control unit 16 compares the reception level of the reception signal with a preset threshold level, and if the reception level exceeds the threshold level, transmits a signal having the reception level. Information of the base station 20 (C
S-ID) is stored in the memory 14 together with the reception level.

FIG. 4 shows that the above (CS)
3 shows an example of a memory map of the handover target table 140 for storing the reception ID and the reception level, and includes a base station identification information storage area 141 and a reception level storage area 142. The base station identification information storage area 141 stores (CS-ID) related to the base station 20 having a reception level equal to or higher than the threshold level held by the PHS terminal 10, and the reception level storage area 142 stores each of these base stations. The magnitude of the reception level of the radio wave from the station 20 is stored.

In the PHS terminal 10, the control unit 1
6 is a base station 2 having a certain threshold level or more as described above.
While searching for “0”, the level of the signal received from the base station 20 during the current call is also monitored. When the reception level of the reception signal from the base station 20 during the call falls below a specified value, the base station 20 receives a predetermined instruction from the connected base station 20 and continues to maintain the call. The handover process for reconnecting to the station 20 is started.

At the start of the handover process, the control unit 16
Refers to the (CS-ID) stored in the memory 14 and starts the handover process for the base station 20 having the (CS-ID). At this time, if (CS-ID) is not stored in the memory 14, switching back to the original base station 20 connected up to that point is performed.

Based on the basic operation described above, detailed operations related to handover and switchback in the PHS terminal 10 of the present invention will be described in detail below with reference to flowcharts shown in FIGS.

First, FIG. 5 shows that the PHS terminal 10
0 and a call slot used during a call (SL in FIG. 3)
4 is a flowchart showing a process of searching for a wireless reception level from the base station 20 as a handover target destination using a different slot (corresponding to another base station search slot SL3 in FIG. 3).

In the other base station search slot, in the standby state (step 501), it is monitored whether or not a start message has been received (step 502). Is received (step 502 YES),
The reception level of the radio signal from the other base station 20 is searched (step 503).

In the search for the radio reception level, the reception level of the radio signal from the other base station 20 is compared with the threshold level held by the PHS terminal 10 (step 504), and the radio reception level is determined. Is equal to or higher than the threshold level (YES in step 504), the (CS-I) of the base station 20 transmitting the signal having the radio reception level is determined.
D) is stored in the memory 14 together with the radio reception level (step 505).

Next, it is monitored whether or not the stop message has been received (step 506). While the stop message has not been received (step 506 NO), step 503 is performed.
In steps 506 to 506, the wireless reception level search processing and search result storage processing of the other base station 20 are continued, and if a stop message is received (step 506 YES), the process returns to the standby state (step 501).

Next, FIG. 6 is a flowchart showing a call disconnection process in a slot (corresponding to SL2 in FIG. 3) used by the PHS terminal 10 during a call. In this call slot, during a call (step 601), it is monitored whether a disconnection message is received (step 60).
2) While no disconnect message is received (step 60)
2NO), the communication state is maintained, and when the disconnection message is received (step 602 YES), a stop message is transmitted to another slot (corresponding to another base station search slot SL3 in FIG. 3) (step 603). ), After further performing the cutting process (step 604), return to the standby state.

FIG. 7 is a flowchart showing a handover process and a return process in a slot (corresponding to SL2 in FIG. 3) used by the PHS terminal 10 during a call. In this call slot, in the standby state (step 701), it is monitored whether or not there is an instruction for transitioning to a busy state (step 702), and while there is no instruction (NO in step 702), the standby state is maintained. , When there is such an instruction (step 702 YES)
Is another slot (other base station search slot S in FIG. 3).
(Corresponding to L3), an activation message is transmitted (step 703), and the state shifts to a busy state (step 70).
4).

In the state during a call, the control unit 16 determines whether or not a handover has occurred (step 705). This determination is made specifically by the PHS terminal 10
In accordance with the fact that the radio signal level from the connected base station 20 to the own terminal 10 falls below the specified level,
This is performed by monitoring whether control information for instructing the transition to the handover has been received. Here, if a handover has occurred (step 705 YES),
The control unit 16 transmits a stop message to the other base station search slot (step 706). Next, the control unit 16 searches the memory 14 and stores (CS) of the other base station 20 in the handover target table 140 shown in FIG.
(ID) is checked (step 707).

If the (CS-ID) of another base station is stored (YES in step 707), the control unit 16
Refers to the (CS-ID) stored in the memory 14 and starts the handover process with the base station 20 having the (CS-ID) as a connection destination (step 70).
8). Subsequently, the control unit 16 monitors the result of the handover (step 709), and determines that the connection result is “success: O
In the case of “K”, the process returns to the process after step 703, and if the connection result is “unsuccessful: NG”, the process of switching back to the original base station 20 is performed (step 71).
0). In step 707, the memory 14
(CS-ID) is not stored in the
07NO) also performs the process of returning the connection to the original base station 20 (step 710).

As described above, in the PHS terminal 10 according to the present invention, during a call, another base station whose radio reception level becomes equal to or higher than a predetermined threshold level using a slot different from the slot used for the call. The station 20 is detected, the base station information is stored in the memory 14, and at the time of transition to handover, a handover process is performed on the corresponding base station 20 based on the base station information stored in the memory 14. When the base station information is not stored in the memory 14, the handover process is not performed and the switching process is performed. According to this control, it is not necessary to search for another base station 20 whose radio reception level is equal to or higher than a predetermined threshold level from the time of transition to handover. The time until the call is terminated, that is, the call unavailable period can be reduced by the search time.

FIG. 8 shows an example of a specific control sequence of the handover process (step 708) in the PHS terminal 10 of the present invention. PHS terminal 10
7, the base station 20 during a call with the PHS terminal 10 performs the PHS
When the received signal from the terminal 10 is degraded in level or reception quality, an instruction to shift to handover (TCH switching instruction) is transmitted to the PHS terminal 10 during a call.

On the other hand, the PHS terminal 10 recognizes that it is a handover by receiving the TCH switching instruction from the base station 20 (switching source CS) during the call,
Transition to handover processing. That is, the PHS terminal 1
0, after receiving the TCH switching instruction, the memory 14
Requesting the corresponding base station 20 (switching destination CS) to establish a link channel based on the (CS-ID) stored in, and thereafter establishing synchronization and setting data, and transitioning to a call state. .

[0037]

As described above, according to the present invention,
By receiving a signal from an adjacent base station using a slot other than the talk slot used for the call in parallel with the call with the connected base station, the adjacent base station whose wireless reception level is equal to or higher than a predetermined threshold level The station is specified, and at the time of transition to the handover, the handover processing or the return processing is immediately started based on the above-described identification result, so that the time from the transition to the handover to the end of the return processing is determined. In addition, the time required to search for another base station whose radio reception level is equal to or higher than the predetermined level can be saved, and the period during which communication cannot be performed can be shortened by that amount to realize smooth operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a system configuration of a PHS according to the present invention.

FIG. 2 is a block diagram showing a functional configuration of a PHS terminal according to one embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a communication slot of the PHS terminal according to the present invention.

FIG. 4 is a diagram showing an example of base station information stored in a PHS terminal according to the present invention.

FIG. 5 is a flowchart showing a search process for a handover target base station of a PHS terminal according to the present invention.

FIG. 6 is a flowchart showing a call disconnection process of the PHS terminal according to the present invention.

FIG. 7 is a flowchart showing handover processing and switchback processing of the PHS terminal according to the present invention.

FIG. 8 is a control sequence of a handover process of the PHS terminal according to the present invention.

FIG. 9 is a diagram for explaining a handover process in a TDMA mobile station.

[Explanation of symbols]

 Reference Signs List 10 PHS terminal (PS) 11 Antenna 12 Wireless unit 13 Communication circuit 14 Memory 140 Handover target table 141 Base station identification information (CS-ID) storage area 142 Reception level storage area 15 Dial input unit 16 Control unit 20 Base station (CS) ) 30 exchange

Claims (8)

[Claims] 1. A function of performing a reconnection process from a connected base station to another base station connected to a base station connected to a public network by a radio line, and a base station capable of reconnection after the reconnection process is started. In a simplified portable telephone terminal having a function of performing a return process for connecting to the original base station when the base station does not exist, during a call with the base station, the adjacent base station uses a slot other than a call slot used for the call. Receiving the signal from
Search means for searching for a base station whose reception level is equal to or higher than a predetermined level; storage means for storing base station information corresponding to the base station searched by the search means; and Reconnection processing means for performing the reconnection processing on the base station corresponding to the base station information stored in the means, and when the transition to the reconnection processing is performed, base station information is not stored in the storage means. In this case, the simple type mobile phone terminal further comprises a return processing means for stopping the reconnection processing and performing the return processing. 2. When a plurality of base station information are stored in the storage means at the time of transition to the reconnection processing, the reconnection processing means performs the reconnection processing in the order of a base station having a higher reception level. The simplified portable telephone terminal according to claim 1, wherein: 3. A function of performing a reconnection process from a connected base station to another base station connected to a base station connected to a public network by a wireless line, and a base station capable of reconnection after a transition of the reconnection process. In a simplified portable telephone terminal having a function of performing a switching process for connecting to an original base station when the base station does not exist, during a call with the base station, a signal other than a talk slot used for the call is transmitted from an adjacent base station. Timing control means for controlling reception of a signal, reception base level of a base station having a reception level of a signal received by a slot other than the communication slot which is equal to or higher than a predetermined level, and transition to the reconnection processing. Connection control means for performing the reconnection processing or the return processing based on a result of specifying the base station by the adjacent base station specifying means. Simple mobile phone terminal. 4. An adjacent base station identifying means for receiving a signal from an adjacent base station using a slot other than the communication slot, and searching for a base station having a reception level equal to or higher than a predetermined level; Storage means for storing base station information corresponding to the base station searched by the means,
Connection control means, when transitioning to the reconnection processing, reconnection processing means for performing the reconnection processing for the base station corresponding to the base station information stored in the storage means, 4. The system according to claim 3, wherein, when the base station information is not stored in the storage unit, the reconnection process is stopped and the switchback processing unit performs the switchback process. Simple mobile phone terminal. 5. A reconnection processing means, in a case where a plurality of pieces of base station information are stored in the storage means at the time of transition to the reconnection processing, performs the reconnection processing in the order of a base station having a higher reception level. The simplified portable telephone terminal according to claim 4, wherein: 6. A function of performing reconnection processing from a connected base station to another base station which is connected to a base station connected to a public network via a wireless line, and a base station which can be reconnected after the reconnection processing is started. In a simplified type portable telephone terminal having a function of performing a return process for connecting to an original base station when there is no frame, transmission and reception frames each composed of a plurality of slots are made frame units, and the transmission and reception frames A plurality of slots are assigned to at least a control slot and a plurality of communication slots, and during a call with the base station, call control means for making a call using one of the plurality of communication slots; A slot timing control means for controlling reception of a signal from an adjacent base station using a communication slot not used for the call during communication with the station; Storage means for storing information indicating an adjacent base station corresponding to a signal received under the control of the mining control means; and information indicating an adjacent base station is not stored in the storage means upon transition to the reconnection processing. In such a case, a re-connection processing means for stopping the re-connection process and performing the re-connection process is provided. 7. The storage means stores information indicating an adjacent base station and information indicating a reception level of a signal from the adjacent base station, and the reconnection processing means stores a plurality of base station information in the storage means. 7. The simplified portable telephone terminal according to claim 6, wherein when stored, the reconnection process is performed in the order of the base station having the higher reception level. 8. The reconnection processing means requests a connection to an adjacent base station stored in the storage means based on a switching instruction from a base station during a call. The simplified mobile phone terminal described.