JP2009188739A - Window-size controller, mobile communication terminal, radio controller, mobile communication system and method for controlling window size in mobile communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a window-size controller controlling the window size of a communication in a radio channel of a mobile communication terminal in a mobile communication system varying the signaling speed of the radio channel. <P>SOLUTION: The window-size controller includes signaling-speed determining sections (126 and 312) determining the signaling speeds in the radio channels from the information of the radio channels and window-size determining sections (120 and 310) determining the window sizes of the communications from the determined signaling speeds. The window-size controller further includes window-size control sections (114 and 308) controlling the window sizes of the communications in the radio channels by the determined window sizes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a window size control apparatus, a mobile communication terminal, a radio control apparatus, a mobile communication system, and a window size control method in a mobile communication terminal, and more specifically, controls a window size based on a window size determined from radio channel information. The present invention relates to a window size control device, a mobile communication terminal, a radio control device, a mobile communication system, and a window size control method in a mobile communication terminal.

  Due to recent developments in communication technology and information processing technology, communication systems are increasing in speed and capacity. In a wireless communication system such as a mobile communication system, it is important to speed up communication and reduce loss in a wireless section, and research and development have been promoted recently.

  Also, in mobile communication systems, research and development of communication methods such as HSDPA (High Speed Downlink Packet Access) that dynamically changes a radio channel according to the state of changing communication quality is being promoted. In the communication method that dynamically changes the setting of the wireless channel, the communication speed is frequently updated with the dynamic change of the wireless channel (see, for example, Non-Patent Document 1).

  Conventionally, there has been known a mobile communication system that realizes an increase in speed and capacity by performing communication control based on transmission quality of a radio channel (for example, see Patent Document 1).

JP 2003-319458 A Yoshiyuki Yasuda et al., “Overview of HSDPA”, NTT Technical Journal, February 2007, p. 32-36, http://www.ntt.co.jp/journal/0702/files/jn200702032.pdf 3GPP TS 34.108, 2007 3GPP TS 25.214, 1999 3GPP TS 25.306, 2003 3GPP TS 25.331, 2004 3GPP TS 25.308, 2004 3GPP TS 25.322, 2000

  However, in a conventional communication system in which communication control is performed after communication is started, an appropriate window size cannot always be set when communication is started, when a communication channel is changed, or when a communication state is changed. There was a problem that the window size of the same size as the initial value or the previously set window size was applied.

  The present invention has been made in view of such problems, and the object of the present invention is to set a window size corresponding to the information of the radio channel at the start of communication, when changing the communication channel, or when changing the communication state. An object of the present invention is to provide a window size control apparatus, a mobile communication terminal, a radio control apparatus, a mobile communication system, and a window size control method in a mobile communication terminal that enable communication with an appropriate window size by setting.

  In order to achieve the above object, the present invention controls the communication window size of the mobile communication terminal in the mobile communication terminal in the mobile communication system in which the communication speed of the wireless channel is variable. A window size control device comprising: means for determining a communication speed of the communication from the information of the radio channel; means for determining a window size of the communication from the determined communication speed; and the determined window size. And means for controlling the communication window size.

  The invention according to claim 2 is the window size control apparatus according to claim 1, further comprising a storage unit for storing a table indicating a relationship between the communication speed and the window size, and means for determining the window size Is characterized in that the communication window size is determined by referring to the table.

  Invention of Claim 3 is the window size control apparatus of Claim 2, Comprising: The means to measure the quality of the said communication, The means to update the said table according to the measured quality of the said communication, Is further provided.

  Invention of Claim 4 is the window size control apparatus of Claim 2 or 3, Comprising: The means to detect the movement condition of the said mobile communication terminal is further provided, The said memory | storage part respectively has the said movement condition A plurality of corresponding tables indicating the relationship between the communication speed and the window size are stored, and the means for determining the window size corresponds to the movement situation detected by the means for detecting the movement situation of the mobile communication terminal. The communication window size is determined by referring to the table.

  A fifth aspect of the present invention is a mobile communication terminal comprising the window size control apparatus according to any one of the first to fourth aspects.

  A sixth aspect of the present invention is a wireless control apparatus comprising the window size control apparatus according to any one of the first to fourth aspects.

  The invention according to claim 7 is a mobile communication system in which a communication speed of a radio channel is variable, and includes a window size control device that controls a window size of communication in the radio channel of a mobile communication terminal of the mobile communication system. The window size control device includes means for determining the communication speed of the communication from the information of the radio channel, means for determining the window size of the communication from the determined communication speed, and the determined window size. And means for controlling the communication window size.

  The invention according to claim 8 is a window size control method for controlling a window size of communication in a radio channel in a mobile communication terminal, wherein the communication speed of the communication is determined from information of the radio channel, and determined A step of determining a window size of the communication from the communication speed; and a step of controlling the window size of the communication according to the determined window size.

  As described above, according to the present invention, when a communication is started, when a communication channel is changed, or when a communication state is changed, a window size corresponding to information on the radio channel is set, so that an appropriate window size can be obtained. Communication is possible.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In this specification, the window size is data including MAC (Medium Access Control) and RLC (Radio Link Control) for HSDPA (High Speed Downlink Packet Access) in a mobile communication system, for example. Although it corresponds to the window size used for the flow control of the PDU (Protocol Data unit) in the link layer (see, for example, Non-Patent Document 1 (FIG. 1)), the present invention is not limited to this. The present invention can also be applied to control of the window size (set in the TCP header of a TCP packet) in TCP (Transmission Control Protocol) corresponding to the transport layer of the OSI reference model.

  FIG. 1 is a configuration diagram showing a mobile communication system according to an embodiment of the present invention. The mobile communication system includes a mobile communication terminal 100, a base station 200, and a radio network controller 300.

  The mobile communication terminal 100 includes an antenna 102, a transmission / reception unit 104, a control unit 116, and a storage unit 124. The mobile communication terminal 100 transmits and receives signals to and from the base station 200 through the antenna 102 and the transmission / reception unit 104 under the control of the control unit 116. Information (wireless channel information) about the radio channel extracted from the signal received by the transmission / reception unit 104 is stored in the storage unit 124 so as to be referred to by other components, or directly provided to other components. Can be configured.

  The control unit 116 includes a window size control unit 114 and a window size determination unit 120. The window size determination unit 120 determines the window size from the radio channel information, and the window size control unit 114 controls the window size of communication transmitted and received in the transmission / reception unit based on the determined window size. The radio channel information can be radio channel information notified from the radio network controller 300 via the radio base station 200 or radio channel information determined based on reception quality at the mobile communication terminal.

  The control unit 116 also includes a communication speed determining unit 126 that determines a communication speed from the wireless channel information. The communication speed determined by the communication speed determination unit 126 can be stored in the storage unit 124 so that other components can refer to it, or can be configured to be directly provided to other components. The window size determination unit 120 can be configured to determine the window size from the determined communication speed. The window size determination unit 120 can be configured to determine a window size corresponding to the determined communication speed based on a predetermined calculation formula. Alternatively, a table indicating the relationship between the communication speed and the window size is stored in the storage unit 124, and the window size determination unit 120 refers to the table in the storage unit 124, thereby determining the window size corresponding to the determined communication speed. Can be configured to determine.

  Furthermore, the mobile communication terminal 100 includes a quality measuring unit 112 that measures quality such as reception characteristics of signals to be transmitted / received, signal block error rate, and data loss rate, and the control unit 116 stores data according to the measured quality. The table 124 may be configured to update the table of the unit 124. The quality measurement includes transmitting / receiving information on the quality of communication transmitted / received to / from radio control apparatus 300 or base station 200 (for example, an index associated with reception quality such as CQI described later). It is. The quality information output from the quality measuring unit 112 is configured to be stored in the storage unit 124 as, for example, a quality history so that other components can refer to it, or directly provided to other components. Can do.

  Furthermore, the mobile communication terminal 100 includes a movement detection unit 118 that detects the movement of the mobile communication terminal, and the storage unit 124 includes a communication speed and a window size corresponding to the movement state (moving or stationary state, or moving speed). The window size determination unit 120 can be configured to determine a window size corresponding to the moving state and the determined communication speed. For example, the movement detection unit 118 estimates whether fading is performed from a quality history, an acceleration sensor, and a positioning system such as GPS (Global Positioning System), or a combination of a positioning system such as GPS (Global Positioning System). It can also be determined, and the moving speed can be detected. Information relating to the movement status output from the movement detection unit 118 can be stored in the storage unit 124 so that other components can be referred to, or can be directly provided to other components.

  In addition, the mobile communication terminal 100 includes an audio processing unit 110 connected to a microphone 106 and a speaker 108. The voice input from the microphone is subjected to signal processing (analog / digital) by the voice processing unit 110 and transmitted to the base station 200 via the transmission / reception unit 104. The signal received from the base station 200 is subjected to signal processing (digital / analog) by the sound processing unit 110 and output from the speaker 108. A window size control unit 114 controls the flow of signal transmission / reception. The mobile communication terminal 100 includes a camera and an image processing unit (not shown), and can be configured to transmit an image taken to the base station 200 via the transmission / reception unit 104. In addition, the mobile communication terminal 100 includes an operation unit 122 and transmits a radio channel setting request signal between the mobile communication terminal and the base station 200 in accordance with a signal input from the operation unit.

  In this specification, the control unit 116 or at least a part of the storage unit 112, the movement detection unit 118, and the quality measurement unit 112 related to the control unit 116 is also referred to as a window size control device.

  The base station 200 includes an antenna 202 and performs radio communication with a mobile communication terminal under the control of the radio control apparatus 300. Base station 200 receives radio channel information (radio channel information) set with mobile communication terminal 100 from radio control apparatus 300 and notifies mobile communication terminal 100 and establishes a radio channel. Further, the base station apparatus can measure the quality of the radio channel with the mobile communication terminal 100 and notify the mobile communication terminal 100 of the quality. Also, information about the quality of the radio channel with the mobile communication terminal 100 can be received from the mobile communication terminal 100, and the radio channel information can be updated and notified to the mobile communication terminal 100.

  Radio control apparatus 300 is connected to one or a plurality of base stations 200 and has a function of controlling them, and is also referred to as an RNC (Radio Network Controller). Radio control apparatus 300 is connected to a core network (not shown) and has a function of controlling communication between the mobile communication terminal and the core network.

  Radio control apparatus 300 includes communication unit 302, radio channel information determination unit 304, radio channel information setting / changing unit 306, window size control unit 308, and window size determination unit 310.

  The communication unit 302 performs communication between the base station and the core network.

  The radio channel information determination unit 304 responds to a communication channel setting request from the mobile communication terminal 100 or the core network, and information on the radio channel set between the mobile communication terminal 100 and the base station 200 (radio channel information) Is notified to the base station 200 via the radio channel information setting / changing unit 306 and the communication unit 302. The radio channel information is further notified to the mobile communication terminal 100 via the base station. Thereby, a radio channel between the mobile communication terminal 100 and the base station 200 is established.

  The radio channel information setting / changing unit 306 notifies the base station 200 of the radio channel information determined by the radio channel information determining unit 304 via the communication unit 302. The transmitted radio channel information is further notified to the mobile communication terminal 100 via the base station. Thereby, a radio channel is established by the changed radio channel information between the mobile communication terminal 100 and the base station 200.

  The radio channel information setting / changing unit 306 changes the radio channel information when the quality of the radio channel between the mobile communication terminal 100 and the base station 200 changes due to fading or the like. Notify the base station 200. The changed radio channel information is further notified to the mobile communication terminal 100 via the base station. Thereby, a radio channel is established by the changed radio channel information between the mobile communication terminal 100 and the base station 200.

  The radio channel information determined by the radio channel information determining unit 304 and the radio channel information setting / changing unit 306 is stored in the storage unit 320 so that it can be referred to by other components, or provided directly to other components. Can be configured.

  The window size control unit 308 and the window size determination unit 310 have functions corresponding to the window size control unit 114 and the window size determination unit 120 provided in the mobile communication terminal 100, respectively. The window size determination unit 310 determines the window size from the radio channel information determined by the radio channel information determination unit 304 or the radio channel information setting / change unit 306 or the radio channel information updated by the base station 200, and performs window size control. Unit 308 controls the window size of communication transmitted / received to / from mobile communication terminal 100 via the transmission / reception unit and the base station based on the determined window size.

  The radio network controller 300 further includes a communication speed determining unit 312 having a function corresponding to the communication speed determining unit 126 provided in the mobile communication terminal. The communication speed determining unit 312 determines the communication speed from the radio channel information determined by the radio channel information determining unit 304 or the radio channel information setting / changing unit 306 or the radio channel information updated by the base station. The communication speed determined by the communication speed determination unit 312 can be stored in the storage unit 320 so that other components can be referred to, or can be directly provided to other components. The window size determination unit 310 can be configured to determine the window size from the determined communication speed. The window size determining unit 310 can be configured to determine a window size corresponding to the determined communication speed based on a predetermined calculation formula. Alternatively, a table indicating the relationship between the communication speed and the window size is stored in the storage unit 320, and the window size determination unit 310 refers to the table in the storage unit 320 to determine the window size corresponding to the determined communication speed. Can be configured to determine.

  Furthermore, the radio network controller 300 includes a quality measuring unit 318 having a function corresponding to the quality measuring unit 112 of the mobile communication terminal 100. The quality measuring unit 318 measures quality such as reception characteristics of signals to be transmitted / received, signal block error rate and data loss rate. The quality measurement includes receiving information about quality notified from the mobile communication terminal 100 or the base station 200. The information about the quality output from the quality measuring unit 318 is configured to be stored in the storage unit 320 as, for example, a quality history so that other components can refer to it, or to be directly provided to other components. be able to.

  The radio network controller 300 also includes a table update unit 314 corresponding to the table update unit 128 of the mobile communication terminal 100. The table update unit 314 can be configured to include a table update unit 314 that updates the table in the storage unit 320 according to the quality measured by the quality measurement unit 318.

  Furthermore, the radio network controller 300 includes a movement detection unit 318 that has a function corresponding to the function of the movement detection unit 118 of the mobile communication terminal 100 and detects the movement of the mobile communication terminal, and the storage unit 320 includes the mobile communication terminal. A table indicating the relationship between the communication speed corresponding to 100 movement states (moving or stationary state) and the window size is stored, and the window size determining unit 310 determines the window size corresponding to the moving state and the determined communication speed. Can be configured to. The movement detector 318 detects the movement of the mobile communication terminal. The movement detection unit 318 detects, for example, a signal related to the update of the location of the mobile communication terminal 100, a home register (HLR) that manages the location of the mobile communication terminal 100, and a visitor location register (VLR). ) Or by receiving notifications from these location registers, it can be determined whether the vehicle is moving or stationary, and the moving speed can be detected (estimated). . Information relating to the movement status output from the movement detection unit 118 can be stored in the storage unit 124 so that other components can be referred to, or can be directly provided to other components.

  In this specification, the window size control unit 308 and the window size determination unit 310, or the window size control unit 308 and the window size determination unit 310, the associated communication speed determination unit 312, the table update unit 314, the movement detection, and the like. Part or all of the unit 316 and the storage unit 320 may be referred to as a window size control device.

<Control of window size in mobile communication terminal>
The window size control operation in the window size control apparatus of the mobile communication terminal will be described with reference to FIGS. FIG. 2 is a flowchart showing an outline of window size control.

  The mobile communication terminal 100 determines whether the control unit 116 detects a window size setting or change event (S202). An event of setting or changing the window size can be a communication start such as detection of a wireless channel setting request signal transmitted in response to an input from the operation unit 122 or reception of a paging signal received by the transmission / reception unit, Alternatively, the wireless communication channel information can be changed during communication.

  At the start of communication, the mobile communication terminal 100 receives the radio channel information determined by the radio channel information determination unit 304 of the radio network controller 300 via the base station 200. When changing the radio communication channel information, the mobile communication terminal 100 receives the changed radio channel information determined by the radio channel setting / changing unit 306 or the base station 200 of the radio network controller 300.

  Next, when an event for setting or changing the window size is detected, the communication speed determining unit 126 of the mobile communication terminal 100 determines the communication speed from the received radio channel information (S204). Details of the method for determining the communication speed will be described later.

  Next, the window size determining unit 120 of the mobile communication terminal 100 determines a window size corresponding to the communication speed determined by the communication speed determining unit 126 (S206). Details of the window size determination method will be described later.

  The mobile communication terminal 100 can control the communication of the mobile communication terminal 100 using the window size determined in this way. When controlling communication in the direction from the mobile communication terminal 100 to the base station 200, a message (for example, WINDOW Size as one of STATUS PDUs (determined window size) is notified to the radio network controller 300. )) (Refer to Non-Patent Document 7 9.2.2.11.3) to control the RLC window, thereby controlling the transmission of the transceiver 104. When controlling communication in the direction from the base station 200 to the mobile communication terminal 100, the window size control unit 114 notifies the radio control apparatus 300 of the determined window size via the transmission / reception unit 104 and the base station 200. Message (for example, the window size is stored in the reserve area of the STATUS PDU) is transmitted to the wireless control device 300, and the wireless control device 300 controls the RLC window using the WINDOW Size (determined window size). Thus, communication is controlled.

(Communication speed determination method 1)
Next, an embodiment of a communication speed determination method will be described. The transmission / reception unit 104 of the mobile communication terminal 100 sets the parameters of the physical layer, the MAC layer, and the RLC layer corresponding to the communication speed of the wireless channel for communication as the wireless channel information included in the signal received from the base station 200 Extraction (for example, wireless parameters shown in the tables of Non-Patent Document 2 6.10.2.4.1.23.1 and 6.10.4.1.25.2.1.1). The extracted parameter combination is associated with the communication speed of a specific wireless channel.

  Therefore, the communication speed determination unit 126 of the mobile communication terminal 100 compares the combination of parameters corresponding to each of a plurality of known communication speeds with the combination of parameters extracted by the transmission / reception unit 104 to thereby determine the communication speed of the radio channel. To decide.

(Communication speed determination method 2)
Furthermore, an embodiment of a method for determining a communication speed when the mobile communication terminal 100 transmits / receives an index (for example, CQI: Channel Quality Index (Non-Patent Document 6)) associated with the reception quality of a radio channel will be described. The index associated with the reception quality is used to notify the transmission side of the quality of the received signal. Both the mobile communication terminal 100 and the base station 200 transmit data size (TB Size: Transport Block Size). ) And modulation / coding scheme (MCS) and index (Table 6A.2), and minimum transmission interval (minimum TTI interval: non-patent document 3) Table 5.1a of Patent Document 4) and a table that associates an index with each other (stored in the storage unit or known to the communication speed determination unit 126). The mobile communication terminal 100 selects an index corresponding to the reception quality and transmits it to the base station 200. The base station 200 that has received the index transmits the data size (TB Size), modulation / coding scheme (MCS), and the like used for the next data transmission to the mobile communication terminal 100 that has transmitted the index. Similarly, the mobile communication terminal 100 receives an index from the base station 200.

  The communication speed determination unit 126 of the mobile communication terminal 100 determines the communication speed using the index associated with the reception quality as the radio channel information.

  The communication speed determining unit 126 of the mobile communication terminal 100 determines the size of data to be transmitted (Transport block Size) and the minimum transmission interval of data from an index associated with the reception quality transmitted / received to / from the base station. .

  Next, the communication speed determining unit 126 of the mobile communication terminal 100 determines the communication speed based on the following equation (1) from the determined size of data to be transmitted and the minimum data transmission interval.

  The size of data to be transmitted is the number of bits per transmission interval, and the transmission interval is a fixed time interval. Therefore, the communication speed in the minimum transmission interval can be determined by Equation (1).

  For example, if the size of data to be transmitted is 5887 bits, the minimum transmission interval is 1 msec, and the transmission interval is 2 msec, the communication speed is about 2.8 Mbps from Equation (1).

(Window size determination method 1)
Next, an embodiment of a window size determination method will be described. The window size determination unit 120 can determine the window size with reference to the table stored in the storage unit 124.

  FIG. 3 is a diagram illustrating an example of a table indicating the relationship between the communication speed and the window size stored in the storage unit 124. The table shown in FIG. 3 stores communication speed, RLC PDU size, and window size.

  The window size determination unit 120 refers to the table shown in FIG. 3 and selects a window size corresponding to the communication speed determined by the communication speed determination unit 126 or is determined by the communication speed determination unit 126. The window size can be determined by selecting a window size corresponding to the combination of the communication speed and the RLC PDU size in the received radio channel information.

  The window size can be defined as the number of RLC PDUs that can be transmitted before receiving an acknowledgment response or an acknowledgment (ACK: Acknowledge) signal. When the window size is determined, the ACK signal is related to the RLC PDU size. The amount of information that can be transmitted before receiving is determined. For example, in FIG. 3, when the communication speed is 32 kbps and the RLC PDU size is 5 kbytes or less, the window size is determined to be 3. At this time, if the RLC PDU size is 5 kbytes, a plurality of PDUs storing information of 15 kbytes can be transmitted. Similarly, when the communication speed is 32 kbps and the RLC PDU size is greater than 5 kbytes and less than or equal to 15 kbytes, the window size is determined to be 3. At this time, if the RLC PDU size is 15 kbytes, a plurality of PDUs storing information of 45 kbytes can be transmitted. Similarly, when the communication speed is 64 kbps and the RLC PDU size is greater than 10 kbytes and less than or equal to 20 kbytes, the window size is determined to be 5. At this time, if the RLC PDU size is 20 kbytes, a plurality of PDUs storing 100 kbytes of information can be transmitted. The same applies to FIGS. 4 and 6 described below. The window size may be an index associated with the number of RLC PDUs that can be transmitted before the ACK signal is received.

  FIG. 4 is a diagram illustrating an example of a table indicating the relationship between the communication speed and the window size stored in the storage unit 124. The table shown in FIG. 4 includes a communication speed, an RLC PDU size, a window size that is referred to when the movement state of the mobile communication terminal is determined to be a stationary state, and a window that is referred to when the movement state is determined to be a movement state. Store the size.

  The window size determining unit 120 refers to the table shown in FIG. 4 and selects a window size corresponding to the movement status detected by the movement detection unit 118 and the communication speed determined by the communication speed determination unit 126. Alternatively, by selecting a window size corresponding to a combination of the movement status detected by the movement detector 118, the communication speed determined by the communication speed determiner 126, and the RLC PDU size of the received radio channel information, The window size can be determined.

(Window size determination method 2)
Further, another embodiment of the window size determination method will be described. The window size determining unit 120 can determine the window size using a predetermined calculation formula.

  The window size determination unit 120 can determine the window size based on the following equation (2) from the communication speed determined by the communication speed determination unit 126 and the RLC PDU size in the received radio channel information.

  Here, the coefficient is a correction value for correcting the communication speed / PLC PDU to a window size suitable for the mobile communication system, and may be a constant, for example.

  For example, when the communication speed is 500 × 1024 bps, the RLC PDU size is 256 bytes, and the coefficient is 0.5, the window size is determined to be 125, and about 32 kbytes of information at the beginning of communication or immediately after the change of the radio channel Can be transmitted.

(How to update the table)
Next, an embodiment of a method for updating a table indicating correspondence between communication speed and window size will be described with reference to FIGS. FIG. 5 is a flowchart illustrating a method for updating a table indicating correspondence between communication speed and window size. FIG. 6 is a view showing a table showing the relationship between the communication speed and the window size, where (a) shows a table before update, and (b) and (c) show tables after update.

  The table update unit 128 of the mobile communication terminal 100 determines whether communication is performed in the transmission / reception unit 104 (S602).

  When the transmission / reception unit 104 determines that communication is in progress, the table updating unit 128 of the mobile communication terminal 100 refers to the error rate of the signal block measured by the quality measurement unit 112 (S604), and It is determined whether the error rate is smaller than a predetermined target block error rate.

  When it is determined that the measured error rate of the signal block is smaller than the predetermined target block error rate, the table update unit 128 of the mobile communication terminal 100 is stored in the storage unit as shown in FIG. The window size of the table indicating the relationship between the communication speed and the window size is increased (S608). On the other hand, when it is determined that the measured error rate of the signal block is equal to or higher than a predetermined target block error rate, the table updating unit 128 of the mobile communication terminal 100 stores the error in the storage unit as shown in FIG. The window size of the table indicating the relationship between the stored communication speed and the window size is reduced (S610).

  In S604, the table update unit 128 of the mobile communication terminal 100 may be configured to determine whether the data loss rate measured by the quality measurement unit 112 is smaller than a predetermined target data loss rate.

<Control of window size in RNC>
Next, a window size control operation in the window size control device of the wireless control device 300 will be described with reference to FIG.

  Similar to the window size control in the mobile communication terminal described above, the radio network controller 300 determines whether a window size setting or changing event has been detected (S202). The event of setting or changing the window size includes reception of a wireless channel setting request from the mobile communication terminal 100 or the core network in the communication unit 302, deterioration of the quality of the wireless channel in the quality measurement unit 320, and mobile communication in the movement detection unit 316. For example, the update of the location information of the terminal can be detected.

  Next, when an event for setting or changing the window size is detected, the communication speed determining unit 312 of the radio network controller 300 communicates from the radio channel information determined by the radio channel information determining unit 304 or the radio channel information setting / changing unit 306. The speed is determined (S204). The details of the method for determining the communication speed are the same as the window size control method in the mobile communication terminal described above, and thus the repeated description is omitted.

  Next, the window size determination unit 310 of the wireless control device 300 determines a window size corresponding to the communication speed determined by the communication speed determination unit 312 (S206). The details of the window size determination method are the same as the window size control method in the mobile communication terminal described above, and thus the repeated description is omitted.

  The radio network controller 300 can control communication of the mobile communication terminal 100 using the window size determined in this way. When controlling communication in the direction from the base station 200 to the mobile communication terminal 100, the window size control unit 308 notifies the communication unit 302 and the base station 200 of the determined window size, so that the mobile communication terminal 100 Control communication. When controlling communication in the direction from the mobile communication terminal 100 to the base station 200, the window size control unit 308 notifies the mobile communication terminal 100 of the determined window size via the communication unit 302 and the base station 200. Then, the mobile communication terminal 100 controls communication using the window size received from the wireless control device 300.

(Method for determining communication speed in wireless control device)
Next, a method for determining the communication speed in the radio network controller 300 will be described. The radio network controller 300 can determine the communication speed in the same manner as the communication speed determination methods 1 and 2 described above.

  The communication speed determination unit 312 of the radio network controller 300 includes a physical layer corresponding to the communication speed of the radio channel for communication from the radio channel information determined by the radio channel information determination unit 304 or the radio channel information setting / changing unit 306, The parameters of each layer of the MAC layer and the RLC layer are extracted. The extracted parameter combination is associated with the communication speed of a specific wireless channel.

  Therefore, the communication speed determination unit 312 of the radio network controller 300 compares the combination of parameters corresponding to each of a plurality of known communication speeds with the combination of parameters extracted by the transmission / reception unit 104 to thereby determine the communication speed of the radio channel. Can be determined.

  When the mobile communication terminal 100 transmits / receives an index (for example, CQI: Channel Quality Index (Non-Patent Document 6)) associated with the reception quality of the radio channel, the radio controller 300 transmits the base station 200 via the communication unit 302. The communication speed determination unit 312 determines the communication speed using the index associated with the reception quality as radio channel information.

  The communication speed determination unit 312 of the radio network controller 300 determines the size of data to be transmitted (Transport block Size) and the minimum transmission interval of data from the index associated with the reception quality transmitted / received to / from the base station. .

  Next, the communication speed can be determined based on the above equation (1) from the determined size of the transmitted data and the minimum transmission interval of the data.

(Method for determining window size in wireless control device)
Next, an example of a window size determination method in the radio network controller 300 will be described. The window size determination unit 310 of the radio network controller 300 determines the window size with reference to the table stored in the storage unit 320, as in the window size determination method 1 described above with reference to FIGS. be able to.

  The window size determination unit 310 refers to the table shown in FIG. 3 and selects a window size corresponding to the communication speed determined by the communication speed determination unit 312 or is determined by the communication speed determination unit 312. The window size is determined by selecting the window size corresponding to the combination of the communication speed and the RLC PDU size among the wireless channel information determined by the wireless channel information determining unit 304 or the wireless channel information setting / changing unit 306. be able to.

  Alternatively, the window size determination unit 120 refers to the table shown in FIG. 4 and selects the window size corresponding to the movement status detected by the movement detection unit 316 and the communication speed determined by the communication speed determination unit 312. Or the movement status detected by the movement detector 316, the communication speed determined by the communication speed determiner 312, and the radio channel information determined by the radio channel information determiner 304 or the radio channel information setting / changing unit 306 The window size can be determined by selecting the window size corresponding to the combination with the RLC PDU size.

  Further, the window size determination unit 310 of the radio network controller 300 can determine the window size using a predetermined calculation formula, as in the window size determination method 2 described above.

  The window size determination unit 310 uses the communication speed determined by the communication speed determination unit 312 and the RLC PDU size in the radio channel information determined by the radio channel information determination unit 304 or the radio channel information setting / change unit 306. The window size can be determined based on the above equation (2).

(Table update method in wireless controller)
Next, an embodiment of a method for updating a table indicating correspondence between communication speed and window size in the radio network controller 300 will be described. The table update unit 314 of the radio network controller 300 updates the table indicating the correspondence between the communication speed and the window size stored in the storage unit 320 in the same manner as the table update method described above with reference to FIGS. Can do.

  Referring to FIG. 5, it is determined whether a radio channel is set between the mobile communication terminal 100 and the base station 200 and communication is being performed (S602).

  If it is determined that the wireless channel is set and communication is in progress, the table updating unit 314 of the wireless control device 300 refers to the error rate of the signal block measured by the quality measuring unit 318 (S604), and the measured signal block Is determined to be smaller than a predetermined target block error rate.

  The table update unit 314 of the wireless control device 300 updates the window size of the table indicating the relationship between the communication speed and the window size stored in the storage unit according to the determination result (S608, S610). In S604, the table update unit 314 of the radio network controller 300 may be configured to determine whether the data loss rate measured by the quality measurement unit 318 is smaller than a predetermined target data loss rate.

  As described above, according to the present invention, by setting the window size according to the wireless channel information notified from the wireless network to the mobile communication terminal, communication with an appropriate window size is possible, and the throughput is reduced. improves. Even if the communication speed of the set wireless channel is changed to a lower speed, the window size can be reduced in advance, so that the amount of retransmission data when data loss occurs can be reduced. it can.

It is a block diagram which shows the mobile communication system concerning one Embodiment of this invention. It is a flowchart which shows the outline | summary of control of the window size concerning one Embodiment of this invention. It is a figure which shows the table which shows the relationship between the communication speed concerning one Embodiment of this invention, and window size. It is a figure which shows the table which shows the relationship between the communication speed concerning one Embodiment of this invention, and window size. It is a flowchart which shows the method to update the table which shows a response | compatibility with the communication speed concerning one Embodiment of this invention, and window size. It is a figure which shows the table which shows the relationship between the communication speed concerning one Embodiment of this invention, and a window size, (a) is a table before an update, (b) And (c) is a figure which shows the table after an update, respectively. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Mobile communication terminal 200 Base station 300 Radio control apparatus 114,308 Window size control part 120,310 Window size determination part 126,312 Communication speed determination part

Claims (8)

A window size control apparatus for controlling a window size of communication in a radio channel of a mobile communication terminal in a mobile communication system in which a communication speed of a radio channel is variable,
Means for determining a communication speed of the communication from information of the wireless channel;
Means for determining a window size of the communication from the determined communication speed;
Means for controlling the communication window size according to the determined window size. A storage unit for storing a table indicating the relationship between the communication speed and the window size;
The window size control apparatus according to claim 1, wherein the window size determining unit determines a communication window size by referring to the table. Means for measuring the quality of the communication;
The window size control device according to claim 2, further comprising means for updating the table according to the measured quality of communication. Means for detecting the movement status of the mobile communication terminal;
The storage unit stores a table indicating a relationship between a plurality of communication speeds and window sizes respectively corresponding to the movement statuses.
The means for determining the window size determines the window size of communication by referring to the table corresponding to the movement status detected by the means for detecting the movement status of the mobile communication terminal. Item 4. The window size control device according to Item 2 or 3.   A mobile communication terminal comprising the window size control device according to any one of claims 1 to 4.   A wireless control device comprising the window size control device according to any one of claims 1 to 4. A mobile communication system in which a communication speed of a radio channel is variable, comprising a window size control device that controls a window size of communication in the radio channel of a mobile communication terminal of the mobile communication system, the window size control device comprising:
Means for determining a communication speed of the communication from information of the wireless channel;
Means for determining a window size of the communication from the determined communication speed;
Means for controlling a window size of the communication according to the determined window size. A window size control method for controlling a window size of communication in a radio channel in a mobile communication terminal,
Determining a communication speed of the communication from wireless channel information;
Determining a window size of the communication from the determined communication speed;
A window size control method in a mobile communication terminal, comprising: controlling the window size of the communication according to the determined window size.

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