JP2011041330A - Radio base station, and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system capable of executing hand-off without deteriorating the service quality of a communication application without depending on the communication capability of a base station. <P>SOLUTION: In a radio base station 100, when a radio communication terminal 300 hands off to a radio base station 200 from its own station, the radio communication terminal 300 notifies the radio base station 200 of the communication level of an application which is being executed. The radio base station 200 sends the radio communication terminal 300 of information for controlling the up communication speed from the radio communication terminal 300 based on the communication level. The radio communication terminal 300 controls the up communication speed based on the information notified from the radio base station 200. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radio communication base station, a radio communication terminal, and a radio communication system used in a radio communication system in which radio base stations having different communication capabilities are mixed.

  In the CDMA2000 1xEV-DO (hereinafter referred to as 1xEV-DO) system, the data communication speed of a wireless communication terminal such as a mobile phone is information instructing to increase or decrease the upper limit of the communication speed transmitted from the base station at every predetermined timing. Control is based on "RAbit (Reverse Activity Bit)" and a threshold value determined when a session is established between the radio communication terminal and the base station.

FIG. 11 is a data communication speed change test table used in the 1xEV-DO system. (See non-patent literature)
As shown in FIG. 11, in 1xEV-DO, the upper limit value 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 bps). 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. 12 is a flowchart illustrating a data communication speed change process performed by a 1xEV-DO compatible wireless communication terminal.

  The 1xEV-DO compatible wireless communication terminal starts communication at the lowest communication speed (9.6 bps) (step 9001).

  When RAbit is received from the base station, it is determined whether or not the received RAbit is “1”. (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 α varies depending on the current communication speed. For example, when the threshold α is to be increased by one step from 9.6 kbps to 19.2 bps, the threshold 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 bps, 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 the direction of lowering 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), and the random number x is compared with the threshold value α (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, the study of CDMA2000 1xEV-DO rev.A (hereinafter referred to as 1xEV-DO rev.A), which is an extension of the above 1xEV-DO (hereinafter referred to as 1xEV-DO rev.0) communication method, is currently in progress. . QoS (Quality of Service) control is a new function added to 1xEV-DO rev.A. QoS control is control in which a priority is given to a packet for each application executed on a wireless communication terminal, and a packet with a higher priority is transferred. 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, 2002 10

When the wireless communication terminal is handed off to the 1xEV-DO rev.0 base station while executing an application that requires a certain communication speed on the wireless communication terminal in the 1xEV-DO rev.A environment First, communication is started from 9.6 kbps, and the required communication speed cannot be obtained unless the communication speed increase test based on the above probability is passed. 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, generally a communication speed of about 70 to 80 kbps is required, but 1xEV-DO rev.0 always starts from 9.6 kbps, and the above communication speed increase test is required at least three times to meet the required speed It becomes. 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 becomes low. Therefore, if a considerable number of tests are not passed, the required speed cannot be obtained. 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-described problem, the radio base station according to the invention described in claim 1 includes: a receiving unit configured to receive an uplink communication speed required by an application when the radio communication terminal executes the application; and the radio communication Provided with a notification means for notifying the other radio base station of the uplink communication speed required by an application being executed by the radio communication terminal when the terminal hands off from the own station to the other radio base station. It is characterized by things.

  According to a second aspect of the present invention, the radio base station sets a threshold for changing the upper limit value of the communication speed set in stages, and sets an uplink communication speed required for an application being executed by the radio communication terminal. A plurality of storage means corresponding to the reception means, and a receiving means for receiving a notification regarding the uplink communication speed required for an application being executed by the wireless communication terminal from another base station in communication with the wireless communication terminal. When the wireless communication terminal handoffs to the own station from the other base station, the threshold corresponding to the uplink communication speed received by the receiving means is acquired from the storage means and notified to the wireless communication terminal And a notification means.

  According to a third aspect of the present invention, when executing an application, the wireless communication terminal includes a notification means for notifying an uplink communication speed required by the application, and another wireless base station from the communicating wireless base station. Receiving means for receiving, from the radio base station, a threshold value for changing the upper limit value of the communication speed set in a stepwise manner determined based on the notified uplink communication speed, and the reception And a control means for controlling the uplink communication speed of the application based on the threshold value received by the means.

  According to a fourth aspect of the present invention, there is provided a wireless communication system according to the first aspect, wherein a first wireless base station capable of assigning a desired uplink communication speed according to an application and an upper limit value of the communication speed are changed stepwise. A wireless communication system comprising: a second wireless base station that controls the communication speed by: a first wireless base station; and a wireless communication terminal that can communicate with the second wireless base station, When the wireless communication terminal executes an application, the wireless communication station 1 receives a reception means for receiving an uplink communication speed required by the application, and the wireless communication terminal performs a handoff from the own station to another wireless base station. The second wireless base station has notification means for notifying the other wireless base station of the uplink communication speed required by the application being executed by the wireless communication terminal. Storage means for storing a plurality of thresholds for changing the upper limit value of the communication speed set in stages corresponding to the uplink communication speed required by the application being executed by the wireless communication terminal; Receiving means for receiving a notification regarding the uplink communication speed required by an application being executed by the wireless communication terminal from one wireless base station, and the wireless communication terminal from the first wireless base station to the local station When the handoff is performed, the threshold value corresponding to the uplink communication speed received by the receiving unit is acquired from the storage unit and notified to the wireless communication terminal, and the wireless communication terminal A notification means for notifying one radio base station of an uplink communication speed required by the application when executing the application, and the second radio base station from the first radio base station. When handing off to the line base station, a threshold value for changing the upper limit value of the communication speed set in stages determined based on the notified uplink communication speed is received from the first radio base station. Receiving means, and control means for controlling the uplink communication speed of the application based on the threshold value received by the receiving means.

  According to the present invention, a handoff from a radio base station that can be assigned a desired uplink communication speed to a radio base station that controls the communication speed by changing the upper limit value of the communication speed in stages is being performed. This can be realized without degrading the service quality of the application.

1 is an overall schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. It is a functional block block diagram of the radio base station which concerns on embodiment of this invention. It is a detailed functional block diagram of a system control unit and a system storage unit of the radio base station according to the embodiment of the present invention. It is a detailed functional block diagram of a system control unit and a system storage unit of the radio base station according to the embodiment of the present invention. It is a functional block diagram of the radio | wireless communication terminal which concerns on embodiment of this invention. It is a detailed functional block diagram of the system control part and system memory | storage part of the radio | wireless communication terminal which concerns on embodiment of this invention. It is a figure which shows an example of the table for a communication speed change test which concerns on embodiment of this invention. It is a figure which shows the operation | movement flow of the radio base station which concerns on embodiment of this invention. It is a figure which shows the operation | movement flow of the radio base station which concerns on embodiment of this invention. It is a figure which shows the operation | movement flow of the radio | wireless communication terminal which concerns on the implementation 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 in the conventional radio | wireless communication terminal.

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

  FIG. 1 is an overall schematic configuration diagram of a radio communication system according to an embodiment of the present invention.

  A radio communication system 10 illustrated in FIG. 1 includes a plurality of radio base stations (base stations 100 and 200) and a radio communication terminal 300. Note that the numbers of the radio base stations and the radio terminals constituting the radio communication terminal 10 are not limited to the numbers shown in FIG.

  The mobile communication system 10 is a wireless communication system according to the CDMA2000 system, and a plurality of systems having different communication capabilities are introduced as a data communication system.

  Specifically, upstream direction: 153.6kbps, downstream direction: 1xEV-DO rev.0 (hereinafter referred to as rev.0) that realizes a data rate of about 2.4Mbps, upstream direction: about 1.8Mbps, downstream direction: about 1xEV-DO rev.A (hereinafter referred to as rev.A) that realizes a data rate of 3.1 Mbps has been introduced.

  The base station 100 is a base station that supports rev.0 and rev.A, and the base station 200 is a base station that supports only rev.0, and forms cells C100 and C200, respectively.

  The radio communication terminal 300 is a terminal that supports rev.0 and rev.A, and performs communication with the radio base stations 100 and 200.

  FIG. 2 is a block configuration diagram of the base station 100.

  As illustrated in FIG. 2, the base station 100 includes an RF unit 110, a system control unit 120, and a system storage unit 130.

  The RF unit 110 transmits and receives radio signals according to CDMA to and from the radio communication terminal 300. In addition, the RF unit 110 performs conversion between the radio signal and the baseband signal, and transmits and receives the baseband signal to and from the system control unit 120.

  The system control unit 120 controls various functions that the base station 100 has. A more detailed functional block diagram of the system control unit 120 relating to the present embodiment will be described later.

  The system storage unit 130 stores various types of information used for control in the base station 100 and the like. More detailed functional blocks of the system storage unit 130 relating to the present embodiment will be described later.

  The radio base station 200 that supports only rev.0 also has the same functional block configuration as the radio base station 100 shown in FIG.

  FIG. 3 is a detailed functional block configuration diagram of the system control unit 120 and the system storage unit 130 in the radio communication base station 100.

  As shown in FIG. 3, the system control unit 120 of the radio communication base station 100 includes a data communication unit 121, a handoff determination unit 122, a handoff execution unit 123, and a communication level notification unit 124.

  The system storage unit 130 includes a peripheral base station revision storage unit 131 and a communication level storage unit 132.

  The data communication unit 121 executes processing related to communication such as image content and music content, and transmission / reception of various control information.

  FIG. 4 is a detailed functional block configuration diagram of the system control unit 120 ′ and the system storage unit 130 ′ in the radio communication base station 200.

  Note that a description of parts having the same configuration as that of the system control unit 120 of the radio base station 100 is omitted.

  4, the system control unit 120 ′ of the radio base station 200 includes a data communication unit 121, a handoff determination unit 122, a handoff execution unit 123, a communication speed change test table notification unit 125, and an RAbit generation unit 126. Configured.

  The system storage unit 130 ′ includes a communication level storage unit 132 and a communication speed change test table storage unit 133.

  Here, a communication speed change test table 150 stored in the communication speed change test table storage unit 133 is shown in FIG.

  In FIG. 7, the communication speed change test table 150 associates a plurality of communication levels with each upper limit value of each uplink communication speed, and provides the above-described probability test threshold value for each communication level. This is different from the conventional communication speed change test table.

  The communication level is a value set based on the communication speed necessary for the application in the communication level setting unit 124. In the present embodiment, the communication level is set in 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.

  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) (100% probability), the communication speed can be maintained at 76.8 kbps.

  FIG. 5 is a block configuration diagram of the wireless communication terminal 300.

  As shown in FIG. 5, the wireless communication terminal 300 includes an RF unit 310, a system control unit 320, a system storage unit 330, a display unit 340, and a key input unit 350.

  The RF unit 310, the system control unit 320, and the system storage unit 330 provide the same functions as the RF unit 110, the system control unit 120, and the system storage unit 130 of the base station 100, respectively.

  The display unit 340 displays image content received through the RF unit 310 and the system control unit 320, and displays operation details (such as an input telephone number and an address).

  The key input unit 350 is configured by a numeric keypad, function keys, and the like, and is an interface used for inputting user operation details.

  FIG. 6 is a detailed functional block configuration diagram of the system control unit 320 and the system storage unit 330.

  As shown in FIG. 6, the system control unit 320 includes a data communication 321, a handoff determination unit 322, a handoff execution unit 323, a communication speed setting unit 324, a random number generation unit 325, and a random number / table comparison unit 326. The

  The system storage unit 330 includes a communication speed change test table storage unit 331 and a communication level storage unit 332.

  The data communication unit 321 sends a RouteUpdate message (candidate base station notification) with a base station having a communication capability different from that of the base station that is performing data communication as a handoff destination candidate base station that is executing the data communication. Send to base station.

  Further, the data communication unit 321 receives the RAbit periodically transmitted from the rev.0 compatible radio base station.

  The handoff determination unit 323 determines whether a base station having a communication capability different from that of the handoff source base station is included in the handoff destination candidate base station.

  The communication speed setting unit 324 sets a communication speed according to the application to be executed.

  The random number generation unit 325 generates a random number x (0 <x <1) periodically at a predetermined timing.

  As will be described in detail later, the random number / table comparison unit 326 stores the communication speed change test table storage unit 331 based on the random number x generated by the random number generation unit 325 and the RAbit periodically received from the base station. The communication speed change test table is referred to, and the communication speed setting unit 324 is notified of the comparison result.

  The communication speed change test table storage unit 331 stores all or part of the communication speed change test table 150 received from the radio base station.

  The communication level storage unit 322 stores a communication level corresponding to an application.

  FIG. 8 is a flowchart showing details of the operation of the radio base station 100.

  When the radio base station 100 starts communication with the radio communication terminal 300, first, the radio base station 100 receives a communication level corresponding to the communication speed required for the currently executing application from the radio terminal 300 (step 801), and the communication level storage unit 132. To remember.

  It is determined whether or not a RouteUpdate message including the base station 200 is received from the wireless communication terminal 300, specifically, a RouteUpdate message indicating that the pilot signal strength of the wireless base station 200 is equal to or greater than a predetermined threshold β ( Step 802). When the RouteUpdate message including the radio base station 200 is received (YES in Step 802), it is determined whether or not the radio base station 200 supports only rev.0 (Step 803).

  When it is determined that the radio base station 200 is not rev.0 (NO in step 803), a normal handoff procedure is performed.

  If it is determined that the base station 200 supports only rev.0 (YES in step 803), the base station 100 subsequently determines whether or not the pilot signal strength of the base station 200 is equal to or greater than a predetermined threshold γ. (Step 804).

  If the RouteUpdate message is received (YES in step 804), the communication level stored in the communication level storage unit 132 is notified to the base station 200 (step 805), and a ConnectionClose message is transmitted to the wireless communication terminal 300 (step 805). 806), the communication with the wireless communication terminal 300 is terminated.

  FIG. 9 is a flowchart showing details of the operation of the radio base station 200.

  When the radio base station 200 is notified of the communication level of the communication application being executed in communication with the radio communication terminal 300 from the radio base station 100 (YES in step 901), the communication speed is set according to the notified communication level. With reference to the change table storage unit 133, a value corresponding to the communication level is extracted to create a communication speed change test table 150 ′ (see FIG. 7), and when the wireless communication terminal 300 has been handed off, The communication speed change test table 150 ′ is transmitted to the wireless communication terminal 300 (step 902).

  For example, when the communication level is notified as “1”, the threshold α corresponding to the communication level “1” is extracted from the communication speed change test table 150 as shown in FIG. 150 ′.

  Thereafter, uplink communication with the wireless communication terminal 300 is controlled based on the communication speed change test table 150 '.

  FIG. 10 is a flowchart showing details of the operation of the wireless communication terminal 300.

  When the radio communication terminal 300 starts an application in the rev.A-compatible cell C100 (step 701), the radio communication terminal 300 notifies the radio base station 100 of the communication level of the application (step 702).

  When handoff from the base station 100 to the base station 200 is determined (step 703), first, it is determined whether or not the base station 200 is rev.0 (step 704), and if it is determined that it is rev.0 (step 704). When the session is established from the base station 200, the communication speed change test table 150 ′ is received (step 705), and the uplink communication speed is controlled based on the received communication speed change test table 150 ′. (Step 706).

  DESCRIPTION OF SYMBOLS 10 ... Wireless communication system, 100, 200 ... Base station, 300 ... Terminal, 110, 310 ... RF part, 120, 320 ... System control part, 130, 330 ... System storage part, 340 ... Display part, 350 ... Input part, 121, 321 ... Data communication unit, 122, 322 ... Handoff determination unit, 123, 133 ... Handoff execution unit, 124 ... Communication level notification unit, 125 ... Table notification unit, 126 ... RAbit generation unit, 324 ... Communication speed setting unit, 325... Random number generation unit, 326... Comparison unit, 131... Revision storage unit, 132 and 332... Communication level storage unit, 133 and 331.

Claims (4)

Receiving means for receiving an uplink communication speed required by the application when the wireless communication terminal executes the application;
Notification means for notifying the other radio base station of the uplink communication speed required by the application being executed by the radio communication terminal when the radio communication terminal hands off from the own station to the other radio base station. A radio base station characterized by comprising: Storage means for storing a plurality of thresholds for changing the upper limit value of the communication speed set in a stepwise manner corresponding to the uplink communication speed required for the application being executed by the wireless communication terminal;
Receiving means for receiving a notification regarding the uplink communication speed required by an application being executed by the wireless communication terminal from another base station in communication with the wireless communication terminal;
When the wireless communication terminal is handed off from the other base station to the own station, the threshold corresponding to the uplink communication speed received by the receiving means is acquired from the storage means and notified to the wireless communication terminal. A radio base station comprising a notification means. A notification means for notifying an upstream communication speed required by the application when executing the application;
When handing off from a wireless base station in communication to another wireless base station, a threshold value for changing the upper limit value of the communication speed set in stages determined based on the notified uplink communication speed, Receiving means for receiving from a radio base station;
A wireless communication terminal comprising: control means for controlling an uplink communication speed of an application based on the threshold value received by the receiving means. A first radio base station capable of assigning a desired uplink communication speed according to an application; a second radio base station that controls the communication speed by changing an upper limit value of the communication speed in stages; A wireless communication system comprising the first wireless base station and a wireless communication terminal capable of communicating with the second wireless base station,
The first radio base station is
Receiving means for receiving an upstream communication speed required by the application when the wireless communication terminal executes the application;
Notification means for notifying the other radio base station of the uplink communication speed required by the application being executed by the radio communication terminal when the radio communication terminal hands off from the own station to the other radio base station. Have
The second radio base station is
Storage means for storing a plurality of thresholds for changing the upper limit value of the communication speed set in stages in correspondence with the uplink communication speed required by the application being executed by the wireless communication terminal;
Receiving means for receiving a notification regarding the uplink communication speed required by the application being executed by the wireless communication terminal from the first wireless base station;
When the wireless communication terminal is handed off to the own station from the first wireless base station, the threshold corresponding to the uplink communication speed received by the receiving means is acquired from the storage means, and the wireless communication terminal Having a notification means to notify,
The wireless communication terminal is
A notification means for notifying the first wireless base station of an uplink communication speed required by the application when the application is executed;
When handing off from the first radio base station to the second radio base station, the upper limit value of the communication speed set in stages determined based on the notified uplink communication speed is changed. Receiving means for receiving a threshold from the first radio base station;
A wireless communication system comprising control means for controlling an uplink communication speed of an application based on the threshold received by the receiving means.

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