JP2009177770A - Base station, and scheduling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively use a time slot by changing over a communication speed without disconnecting data communication between a base station and a mobile station by using half-rate communication. <P>SOLUTION: The base station 110 includes: an allocation change part 216 changing allocation of mobile stations in process of communication to a predetermined number of sub-slots; an allocation transmission part 218 transmitting, to the mobile stations, allocation information including the allocation of the sub-slots changed by the allocation change part 216, and a start frame of wireless communication by the allocation; and a base station communication start part 220 starting wireless communication with the mobile station by the allocation when reaching the start frame. The base station is characterized by carrying out scheduling of communication with the plurality of mobile stations by using half-rate communication. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a base station that performs radio communication using half-rate communication and a scheduling method.

  In recent years, mobile stations represented by PHS (Personal Handyphone System), mobile phones, and the like have become widespread, making it possible to make calls and obtain information regardless of location or time. Such a mobile station is connected to a communication network by performing wireless communication with a base station arranged at a predetermined interval. Here, a time division bidirectional transmission (TDD) method or a frequency division bidirectional transmission (FDD: Frequency Division Duplex) method is used as a method for bidirectional transmission / reception between the base station and the mobile station. The TDD scheme is a scheme in which, for example, a wireless terminal and a base station switch communication timings from one to the other and from the other to the other alternately and in a short time.

  In packet communication in the current wireless communication system using the TDD scheme, when there is no vacancy in the base station time slot, a plurality of packet communication is accommodated in one time slot by performing a scheduling operation. Here, the scheduling operation means that the usage time of one time slot is divided and assigned to a plurality of users. The operation will be described below.

  In the flowchart of FIG. 9, first, communication between the base station 10 and the mobile station 12 is performed (S20). Here, when the mobile station 14 makes a connection request to the base station 10 (S22), the base station 10 schedules the mobile station 12 and the mobile station 14 (S24). When the time allotted to the mobile station 14 by such scheduling is reached, the base station 10 transmits a radio communication release request (S26) to the mobile station 12, and the mobile station 12 releases communication with the base station 10 ( S28), the wireless communication release completion (S30) is transmitted to the base station 10. Then, the base station 10 transmits a connection instruction to the mobile station 14 (S32), and starts communication between the base station 10 and the mobile station 14 (S34).

  After the communication between the base station 10 and the mobile station 14 is performed for a predetermined time, when the allocation time to the mobile station 12 is reached, the base station 10 transmits a radio communication release request (S36) to the mobile station 14, and the mobile station 14 releases the communication with the base station (S38), and transmits the wireless communication release completion (S40) to the base station 10. Then, the base station 10 transmits a connection instruction to the mobile station 12 (S42), and starts communication between the base station 10 and the mobile station 12 again (S44). In the scheduling operation, the release and connection are repeated in this way, so that two mobile stations 12 and 14 are accommodated in one time slot.

  In addition, a technique has been proposed in which one time slot of the TDD scheme is further time-divided and allocated to two users to double the number of accommodated users. A communication method for doubling the number of accommodated users is called half-rate communication, whereas one user 1 time slot is called full-rate communication. The operation of half rate communication will be described below.

  In FIG. 10, the TDD method is explained, and the horizontal axis indicates the passage of time. In the TDD scheme, communication between the mobile station and the base station is performed alternately in units of time-divided frames 50 (50A to 50E). Normally, one mobile station is assigned to one of the time slots 52 obtained by further dividing the frame, and transmission / reception timing is given in the period of the frame 50.

  Half-rate communication is one time slot that is further time-divided into two. When assigning one time slot 52A to 52E of the frames 50A to 50E to two mobile stations, the time slots are alternately allocated. For example, the two mobile stations have time slots 52A, 52C and 52E and time slots 52B and 52D. And occupy each. Therefore, although it is possible to communicate with two mobile stations in one time slot, the communication speed is reduced by half.

Further, in a communication system capable of executing full-rate communication and half-rate communication in parallel as described above, the number of relocations of half-rate communication for allocating full-rate communication to time slots is reduced, and connection delay is shortened. There is also disclosed a technique capable of performing (for example, Patent Document 1).
Japanese Patent Laid-Open No. 7-222237

  However, in the technology involving the scheduling operation described above, the data communication between the base station 10 and the mobile station 12 is not performed between the release of communication S28 and the connection S34 performed at each switching in the scheduling operation of the base station 10, and is wasted. Was spending a lot of time.

  In addition, full rate communication and half rate communication cannot be switched between full rate communication and half rate communication during communication once the rate is set. For example, even if one of the half-rate communications is free, the other half-rate communications cannot occupy the resources, and there is a problem that the slot utilization efficiency is not improved.

  Furthermore, in the technique for reducing the number of rearrangements described above, when other full-rate communication and half-rate communication are already arranged for the time slot to be arranged or rearranged, the arrangement of the time slot is limited.

  Further, such half-rate communication is conventionally used only for voice communication, and has not been applied to data communication.

  In view of such a problem, the present invention provides a wireless communication system and a wireless communication method capable of effectively using time slots by switching communication speed without disconnecting data communication between a base station and a mobile station. It is intended to provide.

In order to solve the above problems, a typical configuration of a radio communication system according to the present invention includes a base station and a mobile station that performs radio communication with the base station using a time division bidirectional transmission (TDD) scheme. In addition, the base station changes the allocation of mobile stations in communication to a predetermined number of subslots obtained by further time-dividing arbitrary time slots of a plurality of time slots time-divided for each frame period in a predetermined number of frames. An allocation transmission unit for transmitting allocation information including allocation of a subslot changed by the allocation change unit and a start frame of radio communication by allocation to the mobile station, and a mobile station by allocation when the start frame is reached A base station communication start unit for starting wireless communication with the mobile station, and an allocation receiving unit for receiving allocation information from the base station, and a radio communication with the base station by allocation when the start frame is reached A mobile station communication initiation unit for initiating, characterized in that it comprises a.

  With this configuration, it becomes possible to change the allocation of mobile stations to subslots without going through processing such as release or connection. In this way, it is possible to release by switching the communication speed without disconnecting data communication between the base station and the mobile station, to shorten the time spent for connection, and to effectively use the time slot.

  Also, by transmitting the start frame, it is possible to synchronize the change timing to the new assignment, and seamless communication speed switching without duplication or omission of data becomes possible.

  The base station further includes an allocation determination unit that determines allocation to a predetermined number of subslots in response to a connection request of a mobile station that is not in communication, and the allocation transmission unit includes subslots determined by the allocation determination unit. Allocation information including allocation and a wireless communication start frame by allocation may be transmitted to the mobile station that has requested connection.

  With this configuration, even when a new mobile station is allocated, the mobile station can accurately grasp the sub-slot allocation and the wireless communication start frame by the allocation, similar to the mobile station in communication. Moreover, even if the time slot is already occupied, the time slot can be made free by the above-described allocation changing unit, and seamless communication speed switching and effective use of the time slot can be achieved.

  The mobile station further includes a possible response unit that transmits to the base station a switchable response indicating that wireless communication can be switched in the start frame, and the base station starts base station communication in response to reception of the switchable response. You may further provide the start control part which functions a part.

  With this configuration, the base station can determine whether or not the mobile station supports the communication speed switching, and the base station and the mobile station can be operated by causing the base station communication start unit to function only when the mobile station is compatible. It is possible to reliably switch the communication speed between the stations.

  The base station further includes a completion notifying unit that transmits to the mobile station a switching completion notification indicating completion of switching of radio communication with the mobile station by allocation and allocation after switching, and the mobile station receives the switching completion notification, If the wireless communication based on the allocation indicated in the notification of switching completion is not performed, a switching confirmation unit for switching to the wireless communication based on the allocation may be further provided.

  With this configuration, the mobile station can recognize that the base station has performed wireless communication based on the assignment indicated in the switch completion notification, and if the mobile station has not switched the communication speed for some reason, the communication is performed. It is possible to quickly switch to speed. Thus, the communication speed can be switched reliably.

  The switching confirmation unit may return to the wireless communication based on the allocation before switching if it does not receive the switching completion notification for a predetermined period after starting the wireless communication with the base station by the allocation.

  With this configuration, if the mobile station fails to receive the switching completion notification, it can be assumed that the communication speed has not been switched at the base station, and the communication speed before switching is returned to the same speed as the base station. Wireless communication can be performed.

  The predetermined number may be two. By adopting the predetermined number 2, that is, half-rate communication that has been conventionally used for voice communication, it is possible to use existing technology and reduce costs.

  In order to solve the above problems, another configuration of the wireless communication system according to the present invention is a base station used in a communication system in which a plurality of mobile stations and a base station perform communication by sharing a TDD communication slot. The time slots may be shared by performing half rate communication based on the fact that the plurality of mobile stations can perform half rate communication.

  Further, based on the fact that a mobile station that newly starts communication does not perform half-rate communication, the time slot sharing may be switched to be performed using full-rate communication.

  The component corresponding to the technical idea in the wireless communication system and the description thereof can be applied to the wireless communication method.

  As described above, in the present invention, it is possible to effectively use time slots by switching the communication speed without disconnecting data communication between the base station and the mobile station.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  In the following embodiments, in order to facilitate understanding, first, a configuration of the entire wireless communication system will be described, and then functions and operations will be described in detail. In addition to the above-described PHS and mobile phone, various electronic devices such as a notebook personal computer and a PDA (Personal Digital Assistant) can be applied as the mobile station of the present embodiment. Here, a PHS terminal is taken as an example. I will explain.

(Wireless communication system 100)
FIG. 1 is a block diagram illustrating a schematic configuration of a wireless communication system 100. The wireless communication system 100 includes a base station 110 (110A, 110B), a PHS terminal 120 (120A, 120B, 120C), a communication network 130 such as an ISDN (Integrated Services Digital Network) and the Internet, and a relay server 140. Is done.

  In the wireless communication system 100, when a user connects a communication line from his / her PHS terminal 120A to the communication partner PHS terminal 120B, the user's PHS terminal 120A requests a wireless connection request to the base station 110A in the wireless communicable area. I do. The base station 110A that has made the wireless connection request allocates a time slot to the PHS terminal 120A, and requests the relay server 140 to establish a communication connection with the communication partner PHS terminal 120B via the communication network 130. Then, relay server 140 selects base station 110B in the wireless communicable area of communication partner PHS terminal 120B, and sets up communication with communication partner PHS terminal 120B.

Here, when another PHS terminal 120C attempts to connect a communication line with the base station 110A during communication of the PHS terminal 120A, the base station 110A allocates a time slot to the PHS terminal 120C. However, if there is no vacancy in the time slot of the base station 110A, for example, the base station 110A time-divides the time slot (full rate) communicating with the PHS terminal 120A into two lines (hereinafter simply referred to as “two-division”), and performs communication. Change the speed. Then, base station 110A allocates PHS terminal 120A and PHS terminal 120C to sub-slots (half rates) divided into two.
Thus, the PHS terminal 120A and the PHS terminal 120C perform communication through the subslot allocated from the base station 110A. In this embodiment, when the time slot is divided into two, the communication speed can be switched without disconnecting the data communication between the base station 110A and the PHS terminal 120A. Further, in the present embodiment, a configuration is described in which the time slot is time-divided into two subslots for easy understanding, but the number of time divisions is not limited to 2, and various integers according to applications Can be applied.

(Base station 110)
The base station 110 in this embodiment will be described in detail. FIG. 2 is a functional block diagram showing the hardware configuration of the base station 110. The base station 110 includes a base station control unit 210, a base station memory 212, and a base station wireless communication unit 214.

  The base station control unit 210 manages and controls the entire base station 110 by a semiconductor integrated circuit including a central processing unit (CPU). The base station control unit 210 supports a call or communication between the PHS terminals 120 using a program in the base station memory 212.

The base station memory 212 is composed of ROM, RAM, EEPROM, nonvolatile RAM, flash memory, HDD (Hard Disk Drive), etc., and programs processed by the base station control unit 210 and data transmitted / received between the PHS terminals 120 Is stored.

  The base station wireless communication unit 214 performs wireless communication with the PHS terminal 120 based on the PHS telephone network. For example, in the present embodiment, a time division bidirectional transmission (TDD) system is employed in which communication is performed by assigning a plurality of time slots obtained by time division of frames in the base station 110 to respective channels.

  The base station control unit 210 also functions as an allocation change unit 216, an allocation transmission unit 218, a base station communication start unit 220, an allocation determination unit 222, a start control unit 224, and a completion notification unit 226.

  The assignment changing unit 216 changes the assignment of subslots communicating with the PHS terminal 120. In the present embodiment, the time slots that are time-divided for each frame period are further time-divided into a predetermined number (two in this embodiment) of subslots. Accordingly, the PHS terminal 120 performs communication through one or all (two) of the subslots. The allocation changing unit 216 controls distribution of PHS terminals to subslots, and changes allocation according to the number of PHS terminals.

  The allocation transmitting unit 218 receives allocation information including the allocation of subslots changed by the allocation changing unit 216, the allocation of subslots determined by the allocation determining unit 222, which will be described later, and the start frame of wireless communication based on the allocation. Transmit to the PHS terminal 120. By transmitting the allocation information to the PHS terminal 120, the information of the base station 110 is shared with the PHS terminal 120, and the change timing of the communication speed by the allocation is synchronized.

  When the base station communication start unit 220 reaches the start frame assigned by the assignment change unit 216, the base station communication start unit 220 starts wireless communication with each PHS terminal 120 using the subslot assigned by the assignment change unit 216.

  The allocation determining unit 222 determines subslot allocation in response to a new communication connection request (not in communication) from the PHS terminal 120.

  In response to reception of the switchable response from the PHS terminal 120, the start control unit 224 confirms that the PHS terminal 120 can support the assignment by the assignment changing unit 216, and causes the base station communication start unit 220 to function. If there is no switchable response from the PHS terminal 120, the PHS terminal 120 is regarded as not corresponding to the allocation, and the base station communication start unit 220 does not function. That is, the communication speed is not changed by the allocation.

  When the base station 110 completes switching to the assigned wireless communication, the completion notification unit 226 transmits a switching completion notification indicating the completion of the switching and the assignment after the switching to the PHS terminal 120.

(PHS terminal 120)
Next, the PHS terminal 120 in this embodiment will be described. FIG. 3 is a functional block diagram showing a hardware configuration of the PHS terminal. The PHS terminal 120 includes a terminal control unit 310, a terminal memory 312, a display unit 314, an operation unit 316, a voice input unit 318, a voice output unit 320, and a terminal wireless communication unit 322. Yes.

  The terminal control unit 310 manages and controls the entire PHS terminal 100 using a semiconductor integrated circuit including a central processing unit (CPU). The terminal control unit 310 naturally performs a call function and a mail distribution function using the PHS terminal 120 using the program in the terminal memory 312.

  The terminal memory 312 includes a ROM, a RAM, an EEPROM, a nonvolatile RAM, a flash memory, an HDD, and the like, and stores a program processed by the terminal control unit 310, audio data, and the like.

  The display unit 314 includes a liquid crystal display, an EL (Electro Luminescence), a PDP (Plasma Display Panel), etc., and is stored in the terminal memory 112 or provided from an application relay server (not shown) via a communication network. A GUI (Graphical User Interface) of a Web browser or an application can be displayed.

  The operation unit 316 includes operation keys such as a keyboard, a cross key, and a joystick, and receives a user operation input.

  The voice input unit 318 is composed of a voice recognition device such as a microphone, and converts the user's voice input during a call into an electrical signal that can be processed in the PHS terminal 120.

  The voice output unit 320 includes a speaker, and converts the voice signal of the other party received by the PHS terminal 120 into voice and outputs the voice. Further, a ring tone, an operation sound by the operation unit 316, an alarm sound, and the like can be output.

  The terminal wireless communication unit 322 performs wireless communication with the base station 110 in the PHS terminal network. As such wireless communication, there is a time division multiplexing method in which a plurality of time slots obtained by time division of frames in the base station 110 are respectively assigned to channels of the PHS terminal 120 for communication.

  The terminal control unit 310 also functions as an assignment receiving unit 324, a mobile station communication starting unit 326, a possible response unit 328, and a switching confirmation unit 330.

  The allocation receiving unit 324 receives the allocation information including the subslot allocation and the wireless communication start frame transmitted from the allocation transmitting unit 218.

  When the mobile station communication start unit 326 reaches the radio communication start frame received by the allocation reception unit 324, the mobile station communication start unit 326 starts radio communication with the base station 110 through the subslot according to the allocation indicated in the allocation information.

  If the communication speed can be switched to the start frame allocated from the base station 110, that is, the possible response unit 328 has the mobile station communication start unit 326 and can perform the function, the base station The fact that it is possible to switch to 110 (switchable response) is transmitted.

  The switching confirmation unit 330 receives the switching completion notification transmitted from the completion notification unit 226 of the base station 110, and if its subslot allocation is not wireless communication based on the allocation indicated in the switching completion notification. That is, when the communication speed is not switched for some reason, the wireless communication is quickly switched to the assigned wireless communication. In addition, after starting the wireless communication with the base station 110 by the allocation, if the switching completion notification that should be received cannot be received for a predetermined period, the communication speed before switching is restored.

  Next, the communication speed change timing by the start frame will be described. FIG. 4 is an explanatory diagram of the communication speed change timing based on the start frame.

  The communication between the base station 110 and the PHS terminal 120 employs a TDD scheme, and a predetermined number of frames 360 (360A, 360B, 360C, 360D, 360E) that are periodically repeated with respect to the time on the horizontal axis. In FIG. 4, the time is divided into four time slots 370 for transmission and reception. Accordingly, one time slot 370A, 370B, 370C, 370D, 370E of each frame 360A, 360B, 360C, 360D, 360E is used for communication between the base station 110 and one PHS terminal 120. The time slot 370 includes two subslots 370A, 370C, 370E,..., Subslots 370B, 370D,. Here, communication using one of the two subslots is referred to as half-rate communication, and communication using both is referred to as full-rate communication.

  FIG. 4A shows a change in assignment from full-rate communication to half-rate communication. The allocation transmitting unit 218 of the base station 110 transmits the allocation information allocated by the allocation changing unit 216 to the PHS terminal 120 through the time slot 370A of the frame 360A (1). In the allocation information, subslot allocation (here, change from full-rate communication to half-rate communication) and a start frame of radio communication by the allocation (here, relatively two frames later) are shown.

  The allocation receiving unit 324 of the PHS terminal 120 receives the allocation information, and the possible response unit 328 indicates a switchable response indicating that wireless communication can be switched to the start frame of the allocation information (two frames after the frame 360A). (2) is transmitted to the base station 110 through the time slot 370B of the frame 360B.

  The start control unit 224 of the base station 110 receives the switchable response from the PHS terminal 120 and causes the base station communication start unit 220 to function. When the frame 360C that is the start frame is reached (3), the base station communication start unit 220 of the base station 110 and the mobile station communication start unit 326 of the PHS terminal 120 start half-rate communication. Therefore, communication between the PHS terminal 120 and the base station 110 is performed only in the subslots 370C and 370E, and the other subslots 370D.

  The completion notification unit 226 of the base station 110 transmits (4) the PHS terminal 120 through the time slot 370C of the frame 360C (4) a switching completion notification indicating completion of switching of wireless communication based on the allocation information.

  By switching from full-rate communication to half-rate communication as described above, the communication occupation amount of the time slot 370 is halved, and no communication is performed in the next frame 360D.

  FIG. 4B shows a change in assignment from half-rate communication to full-rate communication. When the base station 110 allocates an unused subslot to the PHS terminal 120 that performs only half-rate communication, the base station 110 is allocated by the allocation changing unit 216 as in FIG. The allocation information is transmitted to the PHS terminal 120 through the time slot 370A of the currently used frame 360A (5). Here, since time slot 370B is an empty subslot, communication is not performed.

  The PHS terminal 120 receives the allocation information, and the possible response unit 328 transmits (6) a switchable response to the base station 110 through the time slot 370C of the frame 360C.

  When the frame 360D, which is the assigned wireless communication start frame, arrives (7), the base station 110 and the PHS terminal 120 switch from half-rate communication to full-rate communication. Finally, the completion notification unit 226 of the base station 110 transmits (8) a switching completion notification to the PHS terminal 120 through the time slot 370D of the frame 360D, and the switching of the communication speed is completed.

  In this way, by transmitting the full frame communication or half rate communication start frame to the PHS terminal 120, the base station 110 and the PHS terminal 120 can synchronize the change timing to the new allocation. In addition, seamless communication speed switching without data duplication or omission becomes possible.

(Wireless communication method)
A radio communication method between the base station 110 and the PHS terminal 120 in the radio communication system 100 described above will be described in detail below.

  FIG. 5 is a flowchart showing the flow of processing of a wireless communication method that is normally performed. Here, description will be made using the base station 110, the PHS terminal 120A, and another PHS terminal 120C. In this flowchart, the processing operation when the communication speed switching between the base station 110 and the PHS terminal 120A or the PHS terminal 120C is performed normally is shown.

  First, the PHS terminal 120A that desires communication makes a communication connection request to the base station 110 (S500). Receiving the communication request, the base station 110 allocates the PHS terminal 120A to one vacant time slot (two subslots) by full-rate communication (S502), and assigns the allocated time slot and start frame allocation information. Transmit to the PHS terminal 120A (S504). The PHS terminal 120A starts communication based on the allocation information transmitted from the base station 110 (S506).

  In a state where the PHS terminal 120A and the base station 110 are communicating, when the PHS terminal 120C attempts communication and makes a communication connection request to the base station 110 within the communication range (S508), Receiving that there is no space in the time slot, the base station 110 allocates the PHS terminal 120C to the same time slot as the PHS terminal 120A (S510).

  First, the base station 110 transmits allocation information that causes the PHS terminal 120A to switch from full-rate communication to half-rate communication (S512). The PHS terminal 120A receives the allocation information and returns a switchable response to the base station 110 (S514). The base station 110 receives the switchable response and causes the base station communication start unit 220 to function in response to the reception (S516). When the start frame is reached, the base station 110 and the PHS terminal 120A start communication through the assigned wireless communication (half rate communication) (S518). The base station 110 transmits a switch completion notification to the PHS terminal 120A (S520). The PHS terminal 120A that has received the completion notification confirms that it has switched to the assigned wireless communication (S522).

  By changing the allocation of the subslots, one of the two subslots used for communication between the base station 110 and the PHS terminal 120A becomes empty, so the base station 110 allocates the PHS terminal 120C to the empty subslot. (S524). Then, the base station 110 instructs the PHS terminal 120C to establish communication for half rate communication (S526), and starts communication (S528).

  As described above, when the PHS terminal 120C that newly starts communication is allocated to the time slot, the PHS terminal 120C, as with the PHS terminal 120A, accurately grasps the subslot allocation and the wireless communication start frame by the allocation. Can do. Further, even if the time slot is already occupied, the base station 110 can make a time slot assigned to the PHS terminal 120C, and seamless communication speed switching and effective use of the time slot can be achieved.

  Thereafter, when the PHS terminal 120A desires to end communication with the base station 110, a procedure for disconnecting communication with the base station 110 is performed. Here, the base station 110 transmits a wireless communication release request to the PHS terminal 120A (S530). After receiving the wireless communication release request, the PHS terminal 120A releases the wireless communication (S532), and transmits a wireless communication release completion (S534).

  As one of the subslots becomes free as the PHS terminal 120A releases the communication, the base station 110 prompts the PHS terminal 120C to change to full rate communication in order to effectively use the time slot.

  The base station 110 transmits the allocation information whose communication speed is changed to full rate communication to the PHS terminal 120C (S536). The PHS terminal 120C that has received the allocation information transmits a switchable response to the base station 110 (S538). The base station 110 receives the switchable response, prepares for communication start in response to the reception (S540), and starts wireless communication with the PHS terminal 120C from the start frame indicated in the allocation information (S542). The base station 110 transmits a switching completion notification (S544), and the PHS terminal 120C that has received the switching completion notification confirms that the wireless communication is assigned (S546). Thus, one time slot can be used efficiently.

  Further, the base station 110 can always monitor the presence / absence of data, and in the state where both the PHS terminals 120A and 120C are communicatively connected to the base station 110 (S518, S528), data communication is performed in one subslot. If the communication is interrupted, the base station 110 can issue a subslot release request to the PHS terminal 120 when data communication is not performed for a certain period of time.

  FIG. 6 is a flowchart showing another processing flow of the wireless communication method. Here, the processing operation when the PHS terminal 120A is not applied to the present embodiment is described. In the flowchart of FIG. 6, the processes from S500 to S512 are substantially the same as those in FIG.

  For example, when the PHS terminal 120A does not support the embodiment or when some failure occurs in the PHS terminal 120A, the base station 110 transmits allocation information for changing the communication speed to the PHS terminal 120A (S512). Even so, the PHS terminal 120A cannot cope with the allocation information, and the base station 110 does not receive a switchable response (S560).

  Base station 110 continues full-rate communication with PHS terminal 120A unless a switchable response is received.

  FIG. 7 is a flowchart showing still another processing flow of the wireless communication method. Here, a processing operation is described in a case where some failure occurs in the base station 110 and the communication speed cannot be switched in a state where the present embodiment is applied. In the flowchart of FIG. 7, the processes from S500 to S516 are substantially the same as those in FIG.

  The base station 110 and the PHS terminal 120A should start communication through the assigned wireless communication when the start frame is reached, but if the communication speed of the base station 110 is not switched for some reason, the PHS terminal 120A Only the communication speed is switched (S570). However, since the base station 110 that has failed to switch cannot issue a switch completion notification to the PHS terminal 120A (S572), the PHS terminal 120A must receive a switch completion notification for a predetermined period after switching the communication speed. Then, the wireless communication is returned to the wireless communication by the assignment before switching (S574). Thus, the communication speed with the base station 110 is synchronized.

  FIG. 8 is a flowchart showing still another processing flow of the wireless communication method. Here, a processing operation is described in a case where some failure occurs in the PHS terminal 120A and the communication speed cannot be switched in a state where the present embodiment is applied. In the flowchart of FIG. 8, the processes from S500 to S516 are substantially the same as those in FIG.

  The base station 110 and the PHS terminal 120A should start communication through the assigned wireless communication when the start frame is reached, but if the communication speed of the PHS terminal 120A is not switched for some reason, the base station 110 Only the communication speed is switched (S580). However, since the base station 110 whose communication speed has been switched transmits a switching completion notification describing the allocation (S520), the PHS terminal 120A that has failed to switch is set to the allocation indicated in the switching completion notification and to itself. By comparing with the assigned assignment, it is possible to grasp that the communication speed is not the desired communication speed, and the assignment is quickly changed to the assignment shown in the switch completion notification (S582). Thus, the communication speed with the base station 110 is synchronized.

  By using the wireless communication method described above, it is possible to effectively use time slots by switching the communication speed without disconnecting data communication between the base station 110 and the PHS terminal 120. Moreover, even when the switching (assignment) of the communication speeds of the devices is not successful, it is possible to smoothly shift to a normal state.

  Furthermore, in the wireless communication method described above, based on the fact that the base station 110 and the PHS terminal 120 are capable of half-rate communication, it is possible to easily perform a communication scheduling operation by sharing a TDMA time slot. it can.

  In addition, when a mobile station that starts communication newly appears in a place where the time slot is already shared by half-rate communication, if the new mobile station is detected as being capable of half-rate communication by the half-rate availability detection means, The time slot may be shared by half rate communication.

  When it is detected that half-rate communication is not possible, a mobile station that performs “full-rate communication” in which one terminal continuously occupies time slots is disconnected at “predetermined time” or “to another mobile station”. It may be switched to perform a shared scheduling operation by repeating “connection”.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  Note that the steps in the wireless communication method of the present specification do not necessarily have to be processed in chronological order according to the order described in the flowchart, but are executed in parallel or individually (for example, parallel processing or object-based processing). Processing).

  The present invention can be used for a base station and a scheduling method that perform radio communication using half-rate communication.

1 is a block diagram showing a schematic configuration of a wireless communication system. It is the functional block diagram which showed the hardware constitutions of the base station. It is the functional block diagram which showed the hardware constitutions of the PHS terminal. It is explanatory drawing about the change timing of the communication speed by a start frame. It is the flowchart which showed the flow of the process of the radio | wireless communication method performed normally. It is the flowchart which showed the flow of the other process of the radio | wireless communication method. It is the flowchart which showed the flow of the further another process of the radio | wireless communication method. It is the flowchart which showed the flow of the further another process of the radio | wireless communication method. It is the flowchart which showed the flow of the process of the conventional radio | wireless communication method. It is explanatory drawing about the allocation of the conventional slot.

Explanation of symbols

100 radio communication system 110 base station 120 PHS terminal 210 base station control unit 216 allocation change unit 218 allocation transmission unit 220 base station communication start unit 222 allocation determination unit 224 start control unit 226 completion notification unit 310 terminal control unit 324 allocation reception unit 326 Mobile station communication start unit 328 Possible response unit 330 Switching confirmation unit

Claims (9)

A wireless communication system including a base station and a mobile station that performs wireless communication with the base station using a time division bidirectional transmission (TDD) scheme,
The base station
An assignment changing unit for changing assignment of a mobile station in communication to a predetermined number of subslots obtained by further time-dividing an arbitrary time slot of a plurality of time slots time-divided for each frame period in a predetermined frame number period;
An allocation transmitting unit that transmits allocation information including allocation of subslots changed by the allocation changing unit and a start frame of wireless communication by the allocation to a mobile station;
A base station communication start unit that starts radio communication with the mobile station by the allocation when the start frame is reached;
With
The mobile station
An allocation receiver for receiving the allocation information from the base station;
A mobile station communication start unit that starts wireless communication with the base station by the allocation when the start frame is reached;
A wireless communication system comprising: The base station further includes an allocation determination unit that determines allocation to the predetermined number of subslots in response to a connection request of a mobile station other than the one in communication,
The allocation transmission unit transmits allocation information including allocation of subslots determined by the allocation determination unit and a radio communication start frame by the allocation to the mobile station that has made the connection request. Item 2. The wireless communication system according to Item 1. The mobile station further includes a possible response unit that transmits a switchable response indicating that wireless communication can be switched in the start frame to the base station,
The radio communication system according to claim 1, wherein the base station further includes a start control unit that causes the base station communication start unit to function in response to reception of the switchable response. The base station further comprises a completion notifying unit that transmits to the mobile station a switching completion notification indicating completion of switching of wireless communication with the mobile station by the allocation and allocation after switching,
The mobile station further includes a switching confirmation unit that receives the switching completion notification and switches to the wireless communication based on the allocation if the wireless communication based on the allocation indicated in the switching completion notification is not performed. The radio | wireless communications system of any one of Claim 1 to 3.   The switching confirmation unit, after starting wireless communication with the base station by the allocation, returns to the wireless communication by the allocation before switching if the switching completion notification is not received for a predetermined period. The wireless communication system described.   The wireless communication system according to claim 1, wherein the predetermined number is two. A base station used in a communication system in which a plurality of mobile stations and a base station perform communication by sharing a time-division bidirectional transmission (TDD) communication slot,
A base station apparatus that shares the time slot by performing half-rate communication based on the fact that the plurality of mobile stations can perform half-rate communication. The base station according to claim 7, wherein the mobile station that newly starts communication is switched to perform sharing of the time slot using full-rate communication based on the fact that half-rate communication is not performed. A wireless communication method for performing wireless communication using a base station and a mobile station that performs wireless communication with the base station using a time division bidirectional transmission (TDD) scheme,
The base station
Changing the allocation of the mobile station in communication to a predetermined number of subslots obtained by further time-dividing an arbitrary time slot of a plurality of time slots time-divided for each frame period with a predetermined frame number period;
Transmitting allocation information including the subslot allocation changed by the allocation of the mobile station in communication and the radio communication start frame by the allocation to the mobile station;
The mobile station receives the allocation information from the base station;
The radio communication method according to claim 1, wherein the base station and the mobile station start radio communication based on the allocation when a start frame is reached.