JP2010177834A - Radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication apparatus that can suppress the generation of noises during handover even in the BPSK system communication. <P>SOLUTION: The PHS terminal 1 selects one among a plurality of base stations and establishes a connection relating to a voice speech with the selected base station, and it includes a CPU 30 that switches a sound path to a second base station from a first base station when switching the connection destination to the second base station from the first base station. When the BPSK system is selected as a communication system for the second base station, the CPU 30 does not switch the sound path to the second base station from the first base station when receiving the notification of disconnection of wireless channel from the first base station before the reception of a response of call control from the second base station. When the CPU 30 receives a response of call control from the second base station, it switches the sound path to the second base station from the first base station. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus compatible with the BPSK system.

  Conventionally, in a wireless communication system in which one of a plurality of base stations is selected and voice communication is performed, a handover is performed to switch a communication partner base station according to the state of radio waves transmitted from each base station. The If this handover process is executed during a call, the other party's voice may be interrupted during the process. Depending on the type of the wireless system, a method for reducing this interruption time has been proposed (for example, Patent Document 1).

  Handover processing is also performed in PHS (Personal Handy phone System), which is one of wireless communication systems. Furthermore, in a method called fast handover, out of 4 slots that can be used in TDMA (Time Division Multiple Access), empty slots other than the slot that is communicating with the switching source base station (old base station) are used. By using this, another base station is searched and a base station suitable for communication is selected. Then, by switching the audio path after the connection with the selected base station (new base station) is established, it is possible to reduce the time during which the audio is interrupted.

  By the way, in the advanced terminal for PHS, in addition to QPSK (Quadrature Phase Shift Keying) communication, BPSK (Binary Phase Shift Keying) communication is possible. ing. The BPSK method is a phase shift keying method with fewer errors, although the amount of information per time is halved compared to the QPSK method.

  Here, the conditions for switching the voice path in the above-mentioned fast handover are as follows: (1) When a CC (Call Control) call response is received from the new base station, (2) When the voice of the new base station is detected, (3) Specified when FACCH (Fast Associated Control Channel) with the new base station is in a disconnected state and an RT (Radio frequency Transmission management) radio channel disconnection notification from the old base station is received. ing.

  FIG. 7 is a sequence diagram showing a process of high-speed handover to a new base station of the QPSK scheme. Here, an example of processing for performing high-speed handover to a new base station due to degradation of communication quality due to reasons such as the terminal moving during a call between the PHS terminal and the old base station is shown.

  The terminal searches for neighboring base stations (CSs) in the empty slot and selects a new base station. Subsequently, link channel assignment in QPSK is executed by transmitting a link channel establishment request to the selected new base station. Then, the terminal and the new base station establish a communication channel (Tch) in the established link channel establishment phase.

  Next, the terminal and the new base station are connected through an associated control channel (FACCH, SACCH (Slow Associated Control Channel)) to proceed with the negotiation. Specifically, first, when the terminal transmits a CC call setting, the new base station returns a CC call setting acceptance. Subsequently, when the terminal transmits an RT function request, the new base station returns an RT function request response. Furthermore, after the terminal transmits the RT secret key setting, the FACCH is disconnected.

  Here, it is assumed that an RT radio channel disconnection notification is received from the old base station. Then, since the above-mentioned voice path switching condition (3) is satisfied, the terminal switches the voice path from the old base station to the new base station, and starts a QPSK call with the new base station. Thereafter, the disconnection of the RT radio channel with the old base station is completed and the CC response is received from the new base station, thereby completing the handover.

  Note that the timing of receiving the RT radio channel disconnection notification is unknown, and is not necessarily after the FACCH disconnection as shown in FIG. When received before the FACCH is disconnected, the switching of the voice path is another timing that satisfies the condition (1) or (2).

JP 11-146450 A

  On the other hand, in the BPSK system, the format of audio data to be handled and the processing procedure for establishing communication are different. Specifically, matters relating to the voice path switching condition in the above-described QPSK method include that sound detection cannot be performed and that FACCH disconnection processing is not performed because SACCH is not used.

  Therefore, when the voice path switching condition in the QPSK method is applied to the BPSK method as it is, the switching condition is as follows: (1) When a CC response is received from the new base station, (3a) RT radio channel disconnection from the old base station When a notification is received, it becomes two.

  FIG. 8 is a sequence diagram showing a process of high-speed handover to a new BPSK base station. Here, the case where the audio path is switched by the switching condition (3a) is shown.

  Similar to the sequence of FIG. 7, when the terminal transmits a link channel establishment request, BPSK is assigned from the new base station. Then, the terminal and the new base station establish a communication channel (Tch) in the established link channel establishment phase.

  Here, when the communication quality between the terminal and the new base station is also deteriorated, retransmission control occurs due to a transmission / reception error at each stage of the subsequent negotiation, and the processing is delayed. As a result, if the terminal receives a notification of disconnection of the RT radio channel from the old base station before the completion of the negotiation, the terminal switches the voice path to the new base station according to the condition (3a), and the call using the BPSK method is performed. Be started.

  Then, since the new base station is not yet ready for transmitting correct voice data, noise is generated. Further, if the communication quality with the new base station is not improved, noise is generated by passing the voice path through the new base station.

  As described above, when the voice path switching condition in the QPSK method is also applied to the BPSK method, noise may occur in the voice of the call.

  An object of the present invention is to provide a wireless communication apparatus capable of suppressing noise generation during handover even in BPSK communication.

  A radio communication apparatus according to the present invention is a radio communication apparatus that selects one from a plurality of base stations and establishes a connection related to a voice call with the selected base station, and the first base station A control unit that switches a voice path from the first base station to the second base station when the connection destination is switched from the first base station to the second base station, and the control unit communicates with the second base station. When the BPSK method is selected as the communication method, when a radio channel disconnection notification is received from the first base station before receiving a call control response from the second base station, the voice path is When the call control response is received from the second base station without switching from the first base station to the second base station, the voice path is transferred from the first base station to the second base station. It is characterized by switching to a station.

  In addition, when the control unit has received a radio channel disconnection notification from the first base station before receiving a call control response from the second base station, the secret key setting has already been completed. Preferably, the voice path is switched from the first base station to the second base station.

  The wireless communication apparatus according to the present invention further includes a selection unit that selects either a BPSK method or a QPSK method as a communication method with the base station, and the control unit selects the communication method selected by the selection unit. It is preferable to determine and determine a condition for switching the voice path from the first base station to the second base station according to the determined communication method.

  According to the present invention, noise generation at the time of handover can be suppressed even in BPSK communication.

1 is an external perspective view of a PHS terminal according to an embodiment of the present invention. It is a block diagram which shows the function of the PHS terminal which concerns on embodiment of this invention. It is a sequence diagram which shows process example A of the high-speed handover to the new base station of the BPSK system which concerns on embodiment of this invention. It is a sequence diagram which shows process example B of the high-speed handover to the new base station of the BPSK system which concerns on embodiment of this invention. It is a flowchart which shows the flow of a process in CPU which concerns on embodiment of this invention. It is a flowchart which shows the flow of the process which continues from FIG. 5 in CPU which concerns on embodiment of this invention. It is a sequence diagram which shows the process of the high-speed handover to the new base station of a QPSK system. It is a sequence diagram which shows the process of the high-speed handover to the new base station of a BPSK system.

  Hereinafter, an example of a preferred embodiment of the present invention will be described. In addition, although the PHS terminal 1 is demonstrated as an example of a radio | wireless communication apparatus, this invention is not limited to this. For example, the present invention can be applied to various communication devices having a wireless communication function, such as mobile phones other than PHS, PDA (Personal Digital Assistant), and game machines.

  FIG. 1 is an external perspective view of a PHS terminal 1 according to the present embodiment. FIG. 1 shows a so-called foldable terminal form, but the form of the terminal according to the present invention is not limited to this. For example, a sliding type in which one casing is slid in one direction from a state in which both casings are overlapped, or a rotary type in which one casing is rotated around an axis along the overlapping direction ( Turn type), or a type (straight type) in which the operation unit and the display unit are arranged in one housing and does not have a connecting unit.

  The PHS terminal 1 includes an operation unit side body 2 and a display unit side body 3. The operation unit side body 2 includes an operation unit 11 and a microphone 12 to which a voice uttered by a user of the PHS terminal 1 is input on the surface unit 10. The operation unit 11 includes a function setting operation button 13 for activating various functions such as various setting functions, a telephone book function, and a mail function, and an input operation button 14 for inputting numbers of telephone numbers, mail characters, and the like. , And a determination operation button 15 for performing determination and scrolling in various operations.

  The display unit side body 3 includes a display unit 21 for displaying various types of information on the surface unit 20 and a receiver 22 for outputting the voice of the other party of the call.

  Further, the upper end portion of the operation unit side body 2 and the lower end portion of the display unit side body 3 are connected via a hinge mechanism 4. Further, the PHS terminal 1 relatively rotates the operation unit side body 2 and the display unit side body 3 which are connected via the hinge mechanism 4, so that the operation unit side body 2 and the display unit side body 3 are rotated. The body 3 can be in an open state (open state), or the operation unit side body 2 and the display unit side body 3 can be folded (folded state).

  FIG. 2 is a block diagram illustrating functions of the PHS terminal 1 according to the present embodiment. The PHS terminal 1 includes an operation unit 11, a display unit 21, a CPU 30 (control unit, selection unit), a communication unit 31, an antenna 32, a voice control unit 33, and a memory 34.

  The CPU 30 controls the entire PHS terminal 1, and performs predetermined control on the display unit 21, the communication unit 31, the voice control unit 33, and the like, for example. In addition, the CPU 30 receives input from the operation unit 11 and executes various processes. Then, the CPU 30 controls the memory 34 to execute reading of various programs and data and writing of data when executing processing.

  The display unit 21 performs predetermined image processing according to the control of the CPU 30. Then, the processed image data is stored in the frame memory and output to the screen at a predetermined timing.

  The communication unit 31 communicates with an external device in a predetermined use frequency band (for example, 1.9 GHz band). Then, the communication unit 31 demodulates the signal received from the antenna 32, supplies the processed signal to the CPU 30, modulates the signal supplied from the CPU 30, and transmits the signal from the antenna 32 to the external device. As the modulation method at this time, the above-described QPSK method or BPSK method is selected according to the assignment from the base station and the instruction of the CPU 30.

  The audio control unit 33 performs predetermined audio processing on the signal supplied from the communication unit 31 under the control of the CPU 30 and outputs the processed signal to the receiver 22. The receiver 22 outputs the signal supplied from the audio control unit 33 to the outside. This signal may be output from a speaker (not shown) instead of or together with the receiver 22.

  In addition, the voice control unit 33 processes a signal input from the microphone 12 according to the control of the CPU 30 and outputs the processed signal to the communication unit 31. The communication unit 31 performs a predetermined process on the signal supplied from the audio control unit 33 and outputs the processed signal from the antenna 32.

  The memory 34 includes, for example, a working memory and is used for arithmetic processing by the CPU 30. In addition, a program for executing processing according to the present embodiment, various control condition data, and the like are stored. Note that the memory 34 may also serve as a removable external memory.

  The processing contents of the CPU 30 in the high-speed handover to the new BPSK base station will be described below. When performing a high-speed handover to a new base station of the BPSK method, the CPU 30 has transmitted (3b) the RT secret key setting instead of (3a) as a voice path switching condition, and the RT radio channel from the old base station When a disconnection notification is received. That is, the CPU 30 switches the voice path to the new base station according to the two conditions (1) and (3b).

  FIG. 3 is a sequence diagram showing a processing example A of the fast handover to the new base station of the BPSK scheme according to the present embodiment.

  In this example, after the link channel establishment phase, the communication quality with the new base station that is the handover destination deteriorates, and retransmission control occurs due to a transmission / reception error at each stage of negotiation from the FACCH connection to the RT secret key setting. Processing is delayed. As a result, the timing for receiving the notification of disconnection of the RT radio channel is advanced, and the PHS terminal 1 receives the notification of disconnection of the RT radio channel between the RT function request and the RT function request response.

  Although the RT wireless channel disconnection notification has been received, the RT secret key setting has not been transmitted, so the above condition (3b) is not satisfied. Therefore, the CPU 30 only transmits the RT radio channel disconnection completion notification in response to the RT radio channel disconnection notification, waits until the CC response of the condition (1) is received, and then waits for the BPSK call. To start.

  Under the control of the CPU 30, since the voice path is switched after the new base station is ready to transmit correct voice data, the generation of noise can be suppressed.

  FIG. 4 is a sequence diagram showing a processing example B of the fast handover to the new base station of the BPSK scheme according to the present embodiment.

  In this example, the PHS terminal 1 receives the RT radio channel disconnection notification after the RT secret key setting is transmitted. Then, since the above condition (3b) is satisfied, the CPU 30 executes the switching of the voice path at the timing when the notification of disconnection of the RT radio channel is received.

  If the RT secret key setting is completed, the new base station is ready to transmit correct voice data. Therefore, no noise is generated even if a BPSK call is started between the PHS terminal 1 and the new base station at this timing.

  5 and 6 are flowcharts showing the flow of processing in the CPU 30 according to this embodiment. FIG. 5 shows the processing after establishing the communication channel in FIG. 6 until the communication channel with the new base station is established.

  First, in FIG. 5, in step S <b> 1, the CPU 30 searches for neighboring base stations and selects a new base station that is a handover destination. At this time, the CPU 30 measures the electric field strength of each base station, and selects a base station having a predetermined strength or higher or the maximum strength as a new base station to be handed over.

  In step S2, the CPU 30 transmits a link channel (LCH) establishment request to the new base station. Since the PHS terminal 1 is compatible with both QPSK and BPSK, which method is adopted depends on the response of the new base station.

  In step S3, the CPU 30 determines whether or not the link channel allocated from the new base station is BPSK based on the request in step S2. If this determination is YES, that is, if the BPSK method is used, the process proceeds to step S4. If the determination is NO, that is, if the QPSK method is used, the process proceeds to step S5.

  In step S4, the CPU 30 sets the modulation method used for communication with the new base station to the BPSK assigned in step S3.

  In step S5, the CPU 30 sets the modulation method used for communication with the new base station to the QPSK assigned in step S3.

  In step S6, the CPU 30 executes a link channel establishment phase to establish a communication channel (TCH) with the new base station.

  Moving to FIG. 6, in step S <b> 11, the CPU 30 connects the FACCH, which is a protocol layer 2 control channel, with the new base station.

  In step S12, the CPU 30 determines whether or not the modulation scheme set in step S4 or step S5 is the QPSK scheme. If this determination is YES, that is, if the QPSK method is used, the process proceeds to step S13. If the determination is NO, that is, if the BPSK method is used, the process proceeds to step S14.

  In step S13, the CPU 30 performs SACCH connection that is not adopted in the BPSK method in order to establish communication in the QPSK method.

  In step S14, the CPU 30 starts executing a negotiation phase regarding CC (call control) and RT (radio management).

  In step S15, the CPU 30 determines whether or not the modulation scheme set in step S4 or step S5 is the QPSK scheme. If this determination is YES, that is, if the QPSK method is used, the process proceeds to step S16. If the determination is NO, that is, if the BPSK method is used, the process proceeds to step S17.

  In step S16, the CPU 30 disconnects the FACCH connected in step S11, and shifts the connection control channel to a connection using only the SACCH.

  Hereinafter, the CPU 30 appropriately determines whether the set modulation method is the QPSK method or the BPSK method, and adopts a corresponding voice path switching condition to perform subsequent processing.

  In step S17, the CPU 30 determines whether or not the modulation scheme set in step S4 or step S5 is the QPSK scheme. If this determination is YES, that is, if the QPSK method is used, the process proceeds to step S18. If the determination is NO, that is, if the BPSK method is used, the process proceeds to step S19.

  In step S18, the CPU 30 determines whether or not the new base station has been detected. If this determination is YES, the voice path switching condition (2) in the QPSK method is satisfied, and the routine goes to Step S22. On the other hand, if the determination is NO, the process moves to step S19.

  In step S19, the CPU 30 determines whether an RT radio channel disconnection notification is received from the old base station. If this determination is YES, the process proceeds to step S20, and if the determination is NO, the process proceeds to step S21.

  In step S20, the CPU 30 determines whether or not the RT secret key has been set when the modulation method is the BPSK method. If this determination is YES, the voice path switching condition (3b) in the BPSK system is satisfied, and the routine goes to Step S22. On the other hand, if the determination is NO, the process moves to step S21. If the modulation method is the QPSK method, the FACCH has been disconnected in step S16, and the voice path switching condition (3) is satisfied. Therefore, the process proceeds to step S22.

  In step S21, the CPU 30 determines whether a CC response has been received from the new base station. If this determination is YES, since the voice path switching condition (1) in both the QPSK system and the BPSK system is satisfied, the process proceeds to step S22. On the other hand, if the determination is NO, the process returns to step S17 to continue the voice path switching determination.

  In step S22, the CPU 30 opens a voice path with the new base station, and switches voice from the old base station to the new base station.

  As described above, according to the present embodiment, when the modulation scheme is BPSK, when the RT radio channel disconnection notification is received from the old base station, the voice path is not immediately switched. Generation of noise due to starting a voice call before preparation for transmission of correct voice data is completed can be suppressed. Further, since the voice path is switched in response to the reception of the CC response, the voice call can be started after the new base station is ready to transmit the correct voice data, and noise generation can be suppressed.

  Also, when the RT radio channel disconnection notification is received from the old base station, if the RT secret key setting is completed, the voice path is switched at this timing. This makes it possible to determine that the new base station is ready to transmit the correct voice data without waiting for the reception of the CC response, and to switch the voice path more quickly.

  Also, the PHS terminal 1 that can support both QPSK and BPSK determines which modulation method has been selected, and adopts the corresponding voice path switching condition. As a result, regardless of the modulation method, it is possible to switch the audio path at an appropriate timing while suppressing the generation of noise.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 PHS terminal (wireless communication device)
11 operation unit 21 display unit 22 receiver 30 CPU (control unit, selection unit)
31 Communication Unit 32 Antenna 33 Voice Control Unit 34 Memory

Claims (3)

A wireless communication device that selects one from a plurality of base stations and establishes a connection related to a voice call with the selected base station,
A controller that switches a voice path from the first base station to the second base station when switching a connection destination from the first base station to the second base station;
When the BPSK method is selected as the communication method with the second base station, the control unit wirelessly transmits the call control response from the first base station before receiving a call control response from the second base station. When a channel disconnection notification is received, the voice path is not switched from the first base station to the second base station, and when a call control response is received from the second base station, the voice path Is switched from the first base station to the second base station.   When the control unit has received the radio channel disconnection notification from the first base station before receiving the call control response from the second base station, the control unit has already completed the secret key setting. The radio communication apparatus according to claim 1, wherein the voice path is switched from the first base station to the second base station. As a communication method with a base station, a selection unit for selecting either a BPSK method or a QPSK method is provided,
The control unit determines a communication method selected by the selection unit, and determines a condition for switching the voice path from the first base station to the second base station according to the determined communication method. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is a wireless communication apparatus.

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