JP2007150710A - Wireless communication terminal and wireless communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless communication terminal capable of performing communication without degrading service quality of a communication application regardless of the communication capability of a base station.
A wireless communication terminal 100 according to the present invention is based on a communication level set according to a communication speed required by a communication application in a communication level determination unit 141 and a random number x generated by a random number generation unit 142. Thus, the upper limit of the uplink data communication speed is set.
[Selection] Figure 1

Description

  The present invention relates to a wireless communication terminal and a wireless communication method for controlling a communication speed of uplink data by increasing and decreasing an upper limit value stepwise based on probability.

  In the CDMA2000 1xEV-DO (hereinafter referred to as 1xEV-DO) system, the uplink data communication speed of wireless communication terminals such as mobile phones is instructed to increase or decrease the upper limit of the communication speed transmitted from the base station at every predetermined timing. To be controlled based on information “RAbit (Reverse Activity Bit)” to be performed and a threshold value determined when a session between the wireless communication terminal and the base station is established.

  FIG. 7 is a data communication speed change test table used in the 1xEV-DO system (see Non-Patent Document 1).

  As shown in FIG. 7, in 1xEV-DO, the upper limit of the data communication speed is divided into five stages of 9.6 kbps, 19.2 kbps, 38.4 kbps, 76.8 kbps, and 153.6 kbps. When communication is started, communication is first started at the slowest communication speed (9.6 kbps). Thereafter, the wireless communication terminal receives the RAbit given from the base station and adjusts the communication speed.

  RAbit is a bit value that varies depending on the congestion level of the base station to which the wireless communication terminal is currently connected and the peripheral base station to be handed off. In addition, a base station is congested when a large number of wireless communication terminals are connected to the base station or when a communication line is congested.

  When the communication is not congested in the base station, that is, when the communication speed can be increased, RAbit is set to “0”. On the other hand, when it is determined that the communication is congested in the base station, that is, when it is not preferable to increase the communication speed, RAbit is set to “1”.

  FIG. 8 is a flowchart showing a data communication speed change process performed by a 1xEV-DO compatible wireless communication terminal.

  First, the 1xEV-DO compatible wireless communication terminal starts communication at the lowest communication speed (9.6 kbps) (step 9001).

  When RAbit is received from the base station, it is determined whether or not the received RAbit is “0”. (Step 9002). If it is determined that RAbit is “0” (YES in step 9002), the operation is performed to increase the upper limit value of the current communication speed by one step. In this case, the communication speed is configured to be increased probabilistically rather than absolutely.

  First, a random number x (0 <x <1) is generated (step 9003). It is determined whether or not the generated random number x is smaller than a threshold value α for changing the communication speed (step 9004). Here, as shown in FIG. 7, the threshold value α differs depending on the current communication speed. For example, when the threshold value α is to be increased by one step from 9.6 kbps to 19.2 kbps, the threshold value α is “48” divided by “255”. The obtained value is “48/255”. In this example, it is determined whether the random number x is larger or smaller than “48/255”.

  If it is determined that the random number x is smaller than the threshold value α (step 9004), the upper limit value of the current communication speed is increased by one level (step 9005). For example, if the upper limit value of the current communication speed is 9.6 kbps, it is changed to 19.2 kbps, which is one step higher. On the other hand, if it is determined that the random number x is greater than or equal to the threshold value α, the upper limit value of the current communication speed is maintained (step 9006). For example, if the current communication speed is 9.6 kbps, 9.6 kbps is maintained.

  On the other hand, when it is determined that RAbit is “1” (step 9007), the operation is performed in a direction to lower the upper limit value of the current communication speed by one step. That is, first, a random number x (0 <x <1) is generated (step 9007). In order to distinguish the random number x from the threshold value α (the threshold value α when RAbit is “0”, it is expressed as α ′ in the figure. (Step 9008). If it is determined that the random number x is smaller than the threshold value α (YES in step 9008), the upper limit value of the current communication speed is lowered by one step (step 9009). For example, if the current communication speed is 19.2 kbps, it is changed to 9.6 kbps, which is one step lower. On the other hand, if it is determined that the random number x is greater than or equal to the threshold value α (NO in step 9008), the upper limit value of the current communication speed is maintained (step 9006). For example, if the current communication speed is 19.2 kbps, 19.2 kbps is maintained.

  As described above, in the 1xEV-DO system, the wireless communication terminal is configured to transmit at least an uplink based on the RAbit transmitted at a predetermined timing from the base station and the threshold determined when the session between the wireless communication terminal and the base station is established. Controls whether the upper limit of communication speed in communication is increased, decreased, or maintained by one step.

By the way, CDMA2000 1xEV-DO rev.A (hereinafter referred to as 1xEV-DO rev.A, hereinafter referred to as 1xEV-DO rev.0), which is an extension of the above 1xEV-DO communication method, is now known. Consideration is progressing. QoS (Quality of Service) control is a new function added to 1xEV-DO rev.A. The QoS control is a control in which a priority is set for each application executed on the wireless communication terminal and a bandwidth is surely allocated to a communication with a high priority. In other words, the communication speed required by the application executed on the wireless communication terminal can be ensured from the start of communication, instead of controlling the communication speed stepwise according to the probability as described above. Even within, the communication speed can be changed relatively freely according to the communication speed required by the application.
“Cdma2000 High Rate Packet Data Air Interface 3GPP2 C.S0024 Version 4.0 section8.5.6.1.5.2 Rate Control”, 3GPP2, October 2002

  Even when an application that requires a certain communication speed is executed on a wireless communication terminal that supports 1xEV-DO rev.A, if the terminal is in a 1xEV-DO rev.0 environment, communication must be started from 9.6 kbps. The required communication speed cannot be obtained unless the communication speed increase test with the above-described probability is started. However, in the above conventional technique, only one threshold value α is given for each upper limit value of each communication speed, so communication that can be executed at low speed even for communication that requires a certain speed that does not allow delay. However, the increase / decrease of the communication speed of all communication is controlled with the same probability.

  For example, a case where an IP phone is executed will be described. This IP phone converts voice data into IP packets (VoIP) and delivers the voice to the other party via a normal IP network. Since a dedicated voice network (circuit-switched network) is not used, delay is likely to occur on the route. However, since it is a voice call, the delay is not allowed to exceed a certain time. In other words, in general, a communication speed of about 70 to 80 kbps is required, but 1xEV-DO rev.0 always starts with 9.6 kbps, and the above-mentioned communication speed increase test is required at least three times to meet the required speed And Actually, the communication speed increase test described above is governed by probability, and the probability that it can be increased as the communication speed increases, so the required speed cannot be obtained without passing a considerable number of tests. Delay "occurs.

  In addition, IP phones use a method called “silence compression” that does not transmit data on the side that is not speaking, that is, silence is not transferred, so that the bandwidth is effectively used. Data transmission is not performed while listening to the other party's story, but data transmission is started when the conversation starts. In other words, when an IP phone is executed in a 1xEV-DO rev.0 environment, the uplink communication speed when starting to talk during a call always starts from 9.6 kbps, and the communication speed is set to a necessary and sufficient speed in the communication speed increase test described above. Since it takes time to go up, there will always be a delay at the beginning of the conversation.

  In order to solve the above problem, the wireless communication terminal of the invention according to claim 1, storage means for storing a plurality of thresholds according to the communication application for each upper limit value of communication speed set stepwise, Control that, when executing a communication application, selects the threshold corresponding to the communication application from the storage means, and controls the upper limit of the communication speed of uplink data to the radio base station based on the selected threshold Means.

  According to a second aspect of the present invention, there is provided a wireless base station that includes a plurality of communication settings in which optimum thresholds are defined for each upper limit value of communication speed set stepwise according to a communication application. And a control unit that selectively uses the plurality of communication settings according to a communication application to be activated and controls an upper limit value of a communication speed of uplink data to the radio base station. It is characterized by that.

  Further, in the invention according to claim 3 or claim 1, the setting means notifies the radio base station of the threshold value corresponding to the communication application when executing the communication application. It is characterized by.

  Further, the wireless communication method of the invention according to claim 4 stores a plurality of threshold values corresponding to the communication application for each upper limit value of the communication speed set stepwise in advance, and when executing the communication application, A wireless communication method for selecting the threshold according to the communication application and controlling an upper limit value of a communication speed of uplink data to the wireless base station based on the selected threshold.

  According to a fifth aspect of the present invention, there is provided a wireless communication method in which a plurality of communication settings in which optimum threshold values are defined for each upper limit value of communication speed set stepwise according to a communication application are set in a wireless communication terminal. And using the plurality of communication settings according to a communication application to be activated and controlling the upper limit value of the communication speed of uplink data to the radio base station. To do.

  According to the present invention, by preparing a plurality of threshold values α for controlling the increase / decrease of the communication speed, it is possible to increase the communication speed with high probability for the communication requiring a high speed, and the service quality of the communication application is deteriorated. Can be prevented.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a functional configuration of a wireless communication terminal according to the first embodiment of the present invention.

  The wireless communication terminal 100 is a 1xEV-DO rev.A compatible terminal, and the wireless base station 200 is a 1xEV-DO compatible wireless base station.

  The wireless communication terminal 100 includes a communication application execution unit 11 that executes an application such as an IP phone, a data reception unit 12 that receives data from the wireless base station 200, and data that transmits data from the wireless communication terminal 100 to the wireless base station 200. The transmission unit 13 includes a communication level determination unit 141, a random number generation unit 142, an RAbit extraction unit 143, and a communication speed setting unit 144.

  The data reception unit 12 demodulates a radio signal (RF signal) received from the radio base station 200, decodes the demodulated reception data, and provides the communication application execution unit 11 with it.

  The RAbit extraction unit 143 extracts the RAbit periodically transmitted from the radio base station 200 and received by the data reception unit 12 from the data reception unit 12, and provides the extracted RAbit to the communication speed setting unit 144.

  The communication level determination unit 141 determines a communication speed required by the application executed by the communication application execution unit 11, sets a communication level according to the determined communication speed, and notifies the communication speed setting unit 144 of the communication level.

  The random number generation unit 142 periodically generates a random number x (0 <x <1) at a predetermined timing, and gives the generated random number to the communication speed setting unit 144.

  The communication speed setting unit 144 includes a communication speed change test table 150 to be described in detail later. The RAbit notified from the RAbit extraction unit 143, the communication level notified from the communication level determination unit 141, and the random number generation unit 142 Based on the given random number x, an upper limit value of the communication speed of the transmission data is set, and the upper limit value of the set communication speed is notified to the data transmission unit 13.

  The data transmission unit 13 encodes the data received from the communication application execution unit 11 based on the upper limit value of the communication speed notified from the communication speed setting unit 144, and modulates and outputs the data as an RF signal.

  FIG. 2 is a communication speed change test table 150 included in the communication speed setting unit 144 of the wireless communication terminal 100.

  The communication speed change test table 150 associates a plurality of communication levels with each communication speed upper limit value, and provides the above-described probability test threshold value for each communication level. In this respect, the conventional communication speed change test is performed. Different from table.

  The communication level is a value set based on the necessary communication speed determined by the communication level determination unit 141. In the present embodiment, the communication level is divided into four stages from 1 to 4 for each upper limit value of the communication speed. Value is set. However, the method of setting the communication level is not limited to this, and can be set in three steps for each upper limit value of each communication speed. Further, different steps for each upper limit value of the communication speed (for example, at 9.6 kbps) It may be set to 4 levels, 3 levels for 19.2kbps, etc.). Of course, the value of the threshold value α is not limited to the value used in the present embodiment.

  In this embodiment, the communication level is set by the communication level determination unit 141 and given to the communication speed setting unit 144. The communication level determination unit 141 sets the communication speed required by the application to the communication speed setting. The communication level may be set by the communication speed setting unit 144 based on the notification.

  According to the communication speed change test table 150, when the communication level of the application is determined to be “1” and RAbit = 0 (that is, the communication speed can be increased), for example, communication at 9.6 kbps The threshold α corresponding to the level “1” is “255/255”, and α ≧ x (0 <x <1) (probability 100%), so the upper limit of the communication speed is always the next stage 19.2 Increased to kbps. Similarly, even at 19.2 kbps and 38.4 kbps, the threshold α when the communication level is “1” is “255/255”, so it is always raised to the next stage.

  That is, according to the communication speed change test table 150, for an application whose communication level is set to “1”, the upper limit value of the communication speed is reliably increased to 76.8 kbps in three change tests.

  Even when RAbit = 1 (that is, when it is not preferable to increase the communication speed), if the communication level of the application is “1”, for example, the threshold corresponding to the communication level “1” at 76.8 kbps α is “0/255”, and since α <x (0 <x <1) (establishment 100%), the communication speed can be maintained at 76.8 kbps.

  FIG. 3 is a flowchart showing a communication speed setting process performed by the wireless communication terminal 100 according to the first embodiment of this invention.

  When an application is started in the communication application execution unit 11, first, whether the wireless communication terminal 100 is currently in a 1xEV-DO (hereinafter referred to as rev.0) environment, 1xEV-DO rev.A (hereinafter referred to as rev.A). It is determined whether the user is in an environment (step 1001). If it is determined that the user is in the rev.A environment (NO in step 1001), communication is started after following a predetermined procedure (details are omitted because it is not related to the present invention). If it is determined that the user is in the Rev. 0 environment (YES in step 1001), communication is first started at the lowest communication speed (9.6 kbps) (step 1002). Further, the communication level determination unit 141 determines the uplink communication speed necessary for the application, sets an appropriate communication level, and notifies the communication speed setting unit 144 (step 1003). When the RAbit is received from the radio base station, it is determined whether or not the received RAbit is “0”. (Step 1004). If it is determined that RAbit is “0” (YES in step 1004), the operation is performed to increase the upper limit value of the current communication speed by one step. The random number generation unit 142 generates a random number x (0 <x <1) and supplies it to the communication speed setting unit 144 (step 1005). The communication speed setting unit 144 sets the upper limit value of the current communication speed (at the start of communication). 9.6 kbps) and the communication level notified from the communication level discriminating unit 141 are compared with the random number x (step 1006). If it is determined that the random number x is smaller than the threshold α (in step 1006) YES), the upper limit value of the current communication speed is increased by one step (step 1007). On the other hand, if it is determined that the random number x is greater than or equal to the threshold value α, the upper limit value of the current communication speed is maintained (step 1008).

  If it is determined that RAbit is “1” (NO in step 1004), the upper limit value of the current communication speed is lowered by one step. The random number generation unit 142 generates a random number x (0 <x <1) and supplies it to the communication speed setting unit 144 (step 1009). The communication speed setting unit 144 sets the upper limit value of the current communication speed and the communication level determination unit. 141 is compared with a threshold value α (referred to as α ′ in the figure to distinguish it from the threshold value α when RAbit is “0”) corresponding to the communication level notified from 141 and the random number x (step 1010). ), If it is determined that the random number x is smaller than the threshold value α (YES in step 1006), the upper limit value of the current communication speed is lowered by one step (step 1007), and if the random number x is determined to be greater than or equal to the threshold value α The upper limit value of the current communication speed is maintained (step 1008).

  Note that the communication level set by the communication level determination unit 141 may be notified to the radio base station 200. Thereby, the radio base station 200 can grasp the state of each radio communication terminal and can be used for traffic control and the like.

  FIG. 4 is a block diagram showing functional configurations of the radio communication terminal and the radio base station according to the second embodiment of the present invention.

  The radio communication terminal 300 is a rev.A compatible terminal, and the radio base station 400 is a rev.0 compatible radio base station.

  The wireless communication terminal 300 includes a communication application execution unit 11 that executes an application such as an IP phone, a data reception unit 12 that receives data from the wireless base station 400, and data that transmits data from the wireless communication terminal 300 to the wireless base station 400. The transmission unit 13 includes a communication level determination unit 141, a random number generation unit 142, a RAbit extraction unit 143, a communication setting unit 311, and a communication setting switching unit 312.

  The base station 400 includes a data receiving unit 41 that receives data from a radio communication terminal and the like, a data transmission unit 42 that transmits data to the radio communication terminal and the like, and further includes a RAbit generation unit 431 and a communication setting unit 432. It comprises.

  In the wireless communication terminal 300, the data reception unit 12 demodulates the RF signal received from the wireless base station, decodes the demodulated reception data, and provides the communication application execution unit 110 with the decoded reception data.

  The communication setting unit 311 performs communication settings with the radio base station 400 when the radio communication terminal 300 is turned on.

  Here, the communication setting unit 311 sets a plurality of communication settings with the base station 400 for each communication level described above.

  That is, as shown in FIG. 5, for example, as a communication setting corresponding to the communication level “1”, the threshold α corresponding to the communication level “1” at each stage is extracted from the communication speed change test table 150 to Set to (1). Similarly, communication settings corresponding to the communication level “2” (2), communication settings corresponding to the communication level “3” (3)... The communication setting switching unit 312 holds a plurality of communication settings obtained as a result.

  The communication setting switching unit 312 stores and holds communication settings for each communication level set by the communication setting unit 311, and communicates with the radio base station 400 according to the communication level notified from the communication level determination unit 141. Switch the communication setting to an appropriate communication setting.

  On the other hand, in the radio base station 400, the data reception unit 410 receives data from the radio communication terminal 300 and the like, and the data transmission unit 420 transmits data to the radio communication terminal 300 and the like.

  The RAbit generator 431 generates an RAbit that instructs to increase or decrease the communication speed depending on the degree of communication congestion.

  The communication setting unit 432 establishes and stores a plurality of communication settings with the wireless communication terminal 300 when the wireless communication terminal 300 is powered on.

  That is, in the present embodiment, the wireless communication terminal 300 defines a plurality of threshold values α that are optimum for each communication speed for each communication level when communication settings are normally performed with the wireless base station 400 when the power is turned on. The communication settings are switched and used according to the communication level of the communication application to be started.

  FIG. 6 is a flowchart showing the operation of the wireless communication terminal 300 according to the second embodiment of this invention.

  When the wireless communication terminal 300 is turned on, first, the communication setting unit 311 sets a plurality of communication settings for each communication level with the base station 400 (step 3002).

  When the communication application is started by the communication application execution unit 11 (step 3003), the communication level determination unit 141 determines the communication level of the application (step 3004), and gives the determined communication level to the communication setting switching unit 312. The communication setting switching unit 312 selects an appropriate one from a plurality of communication settings based on the communication level notified from the communication level determining unit 141 (step 3005), and the wireless communication terminal 300 uses the selected communication setting. Starts communication (step 3006).

  When receiving the RAbit from the radio base station 400, the radio communication terminal 300 determines whether or not the received RAbit is “0”. (Step 3007). If it is determined that RAbit is “0” (YES in step 3007), the operation is performed in the direction of increasing the upper limit value of the current communication speed by one step. The random number generation unit 142 generates a random number x (0 <x <1) and supplies it to the communication setting switching unit 312 (step 3008). The communication setting switching unit 312 determines the upper limit value of the current communication speed in the current communication setting. The threshold value α corresponding to (9.6 kbps at the start of communication) is compared with the random number x (step 3009), and if it is determined that the random number x is smaller than the threshold value α (YES in step 3009), the current communication speed The upper limit value is increased by one step (step 3010). On the other hand, if it is determined that the random number x is greater than or equal to the threshold value α, the upper limit value of the current communication speed is maintained (step 3011).

  On the other hand, if it is determined that RAbit is “1” (NO in step 3007), the upper limit value of the current communication speed is lowered by one step. The random number generation unit 142 generates a random number x (0 <x <1) and supplies it to the communication setting switching unit (step 3012). The communication setting unit 311 determines that the upper limit value of the current communication speed and the communication level determination unit 141 The threshold value α corresponding to the notified communication level (in order to distinguish from the threshold value α when RAbit is “0”, it is expressed as α ′ in the drawing) and the random number x are compared (step 3013), If it is determined that the random number x is smaller than the threshold value α (YES in step 3013), the upper limit value of the current communication speed is lowered by one step (step 3013), and if it is determined that the random number x is greater than or equal to the threshold value α, The upper limit value of the communication speed is maintained (step 3014).

  As described above, according to the second embodiment, at the time of communication setting at power-on, a plurality of communication settings are defined that define the optimum threshold α for each communication speed for each of a plurality of communication levels according to the application. Therefore, when a communication application is activated, it is only necessary to select an optimum communication setting for the application, and an optimum communication environment can be provided without imposing a load on the process at the time of application activation.

It is a block block diagram of the radio | wireless communication terminal which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the communication speed change test table which concerns on the 1st Embodiment of this invention. It is a figure which shows the operation | movement flow of the radio | wireless communication terminal which concerns on the 1st Embodiment of this invention. It is a block block diagram of the radio | wireless communication terminal and radio | wireless base station which concern on the 2nd Embodiment of this invention. It is a figure which shows an example of the communication speed change test table and communication setting which concern on the 2nd Embodiment of this invention. It is a figure which shows the operation | movement flow of the radio | wireless communication terminal which concerns on the 2nd Embodiment of this invention. It is a figure which shows the conventional communication speed change test table. It is a figure which shows the operation | movement flow of the communication speed change of the conventional radio | wireless communication terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,300 ... Wireless communication terminal, 200,400 ... Wireless base station, 11 ... Communication application execution part, 12, 41 ... Data reception part, 13, 42 ... Data transmission part, 141 ... Communication level determination part, 142 ... Random number generation 143 ... RAbit extraction unit 144 ... Communication speed setting unit 311 ... Communication setting switching unit 312, 432 ... Communication setting unit 431, RAbit generation unit

Claims (5)

Storage means for storing a plurality of threshold values corresponding to communication applications for each upper limit value of communication speed set in stages;
Control that, when executing a communication application, selects the threshold corresponding to the communication application from the storage means, and controls the upper limit of the communication speed of uplink data to the radio base station based on the selected threshold And a wireless communication terminal. In accordance with the communication application, a setting means for setting a plurality of communication settings defining an optimum threshold value for each upper limit value of the communication speed set stepwise in advance with the radio base station,
A radio communication terminal comprising: a control unit that selectively uses the plurality of communication settings according to a communication application to be activated and controls an upper limit value of a communication speed of uplink data to the radio base station. The wireless communication terminal according to claim 1, wherein when executing the communication application, the control unit notifies the wireless base station of the threshold value corresponding to the communication application. For each communication speed upper limit value set stepwise in advance, store a plurality of thresholds according to the communication application,
A wireless communication method that, when executing a communication application, selects the threshold corresponding to the communication application, and controls an upper limit value of a communication speed of uplink data to the wireless base station based on the selected threshold. Depending on the communication application, a plurality of communication settings defining an optimum threshold value for each upper limit value of communication speed set in stages are set between the wireless communication terminal and the wireless base station,
A radio communication method, wherein the upper limit value of the uplink data communication speed to the radio base station is controlled by selectively using the plurality of communication settings according to a communication application to be activated.

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