JP2012060435A - Method and device of controlling wireless communication traffic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device of controlling traffic by which precious wireless resources are not occupied uselessly by a session in which a throughput is suppressed to a low level by a token bucket algorithm.SOLUTION: A throughput detection part 101 detects a throughput R0. A threshold storage part 102 stores a threshold Rref of the throughput R0 by which a congestion condition of a network side can be estimated. A comparator 103 compares a current throughput R0 with the threshold Rref. A resource release request part 104 sends a request for releasing a wireless resource to a communication controller 100 when the throughput R0 becomes lower than the threshold Rref. The communication controller 100 arbitrarily disconnects a physical layer or a logical layer in a wireless section to release the wireless resource in response to the release request. A release period deciding part 105 decides a release period of the wireless resource. A wireless resource acquiring part 106 acquires the released wireless resource after a lapse of the release period again to resume the wireless communication.

Description

  The present invention relates to a wireless communication traffic control method and apparatus, and more particularly to a traffic control method and apparatus suitable for wireless communication in which a communication band is controlled by a token bucket algorithm.

  As a technique for controlling the communication band according to the degree of network congestion, Patent Document 1 discloses a technique for restricting input / output of a transfer buffer using a token bucket algorithm. The token bucket algorithm basically consists of a token rate and a token buffer. The token is a communication right for the amount of data transferred by the communication device, and the token rate is a throughput that is at least allowed for the communication device. The token buffer is replenished over time at the token rate. If there is a communication right (token) in the token buffer, the communication device can immediately transmit data in bursts according to the amount of the communication right. On the other hand, if the token buffer is empty, the minimum communication bandwidth depending on the token rate Communication is allowed only with.

  According to such a token bucket algorithm, while some users can control unfairness that occupies communication resources by repeating bursty downloads, for many users who download between web browsing, Since the token buffer can be sufficiently filled while browsing the Web, burst downloads are possible during download, and a stress-free use feeling can be obtained.

  However, in the conventional token bucket algorithm, the degree of congestion on the network side is estimated based on the communication execution throughput, so if the token buffer becomes empty and the throughput is restricted by the token rate, the communication execution throughput is reduced. It becomes impossible to measure accurately. For this reason, there is a technical problem that even if the network side congestion is subsequently eliminated, this is not immediately reflected in the throughput of the communication apparatus.

  In Patent Document 1, in order to solve the above technical problem, the token rate is not reviewed while sufficient tokens are not stored in the token buffer, or the tokens are forced to be stored in the token buffer. A technique is disclosed in which burst communication is performed by inserting, execution throughput is measured during that time, and the token rate is accurately linked to the congestion status of the network by reflecting it in the token rate.

JP 2007-189592 A

  In the above-described conventional technique, when congestion on the network side is detected, the token rate is lowered, and accordingly, the throughput of the communication apparatus is also kept low. However, since the communication resource remains allocated to the communication terminal even if the throughput is suppressed, for example, when the wireless terminal communicates by relaying the wireless base station, the session between the wireless terminal and the wireless base station is: Even if the throughput is kept low by the token bucket algorithm, it is maintained. Therefore, valuable radio resources such as a session bandwidth in a radio section and a connection capacity of a radio base station are unnecessarily occupied by a session with low throughput.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to control a traffic control for wireless communication in which a valuable wireless resource is not unnecessarily occupied by a session whose throughput is kept low by a token bucket algorithm. Is to provide.

  In order to achieve the above object, the present invention employs traffic control by a token bucket algorithm for radio communication that relays a radio base station, and in a traffic control device for radio communication in which throughput is controlled according to a token rate, It is characterized by the following measures.

  (1) Means for detecting communication throughput, means for comparing the throughput with a threshold that is estimated that the network side is congested, and if the throughput falls below the threshold, at least a part of the occupied radio resources Means for releasing, means for determining a release period of radio resources, and means for resuming communication by securing the released radio resources after elapse of the release period from release of radio resources.

  (2) When the communication throughput falls below the threshold, the means for releasing the radio resource releases the session band occupied by the radio section by disconnecting the physical link while maintaining the logical link.

  (3) The means for releasing radio resources releases the connection capacity occupied by the radio base station by disconnecting the logical link together with the physical link when the communication throughput falls below the threshold.

  (4) When the communication throughput falls below the threshold, the means for releasing radio resources occupies the radio section by keeping the logical link and keeping the throughput at a regulated rate lower than the throughput corresponding to the token rate. A part of the session bandwidth was released.

  According to the present invention, the following effects are achieved.

  (1) In wireless communication traffic control using the token bucket algorithm, if the wireless section or network is congested and the token rate decreases, and the wireless communication throughput decreases accordingly, the occupied wireless resources are temporarily stored. After that, the wireless communication is acquired again and the wireless communication is resumed, so that it is possible to prevent a session that cannot obtain high throughput due to network congestion from occupying valuable wireless resources unnecessarily. become. In addition, the token buffer is restored after the release period, and burst communication is possible, so that the token rate can be accurately reviewed.

  (2) Since the physical link is disconnected while maintaining the logical link in order to release the radio resource, the session band occupied in the radio section can be released. Further, since the logical link is maintained, wireless communication can be resumed quickly.

  (3) Since not only physical links but also logical links are disconnected in order to release radio resources, in addition to releasing session bandwidth occupied in the radio section, the connection capacity of radio base stations can be released. Become.

  (4) In order to release radio resources, while maintaining the logical link, the throughput is restricted to a regulated rate lower than the token rate, so the session bandwidth occupied in the radio section while maintaining radio communication Part of it can be released.

1 is a block diagram of a wireless network to which a traffic control system of the present invention is applied. It is the figure which showed the structure which concerns on the token bucket of a radio | wireless communication modem. It is the block diagram which showed the structure which concerns on the traffic control of a radio | wireless terminal. It is the flowchart which showed the operation | movement of 1st Embodiment of this invention. It is a time chart of a 1st embodiment. It is the flowchart which showed the determination method of release period Trelease1 in 1st Embodiment. It is the flowchart which showed the operation | movement of 2nd Embodiment of this invention. It is a time chart of a 2nd embodiment. It is the flowchart which showed the determination method of release period Trelease2 in 2nd Embodiment. It is a flowchart of the modification of 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a wireless network to which the traffic control system of the present invention is applied. A wireless terminal 1 such as a personal computer, a PDA or a smartphone, and a wireless device attached to or built in the wireless terminal 1 are shown. The wireless terminal 1 includes a communication modem 2 and a wireless base station 3 that establishes a wireless link between the wireless communication modem 2, and the wireless terminal 1 passes through the wireless communication modem 2, the wireless base station 3, and a wide area network 4 such as the Internet. Then, it communicates with the opposing peer 5. The wireless communication model 2 employs a token bucket algorithm for traffic control, and is a token rate Rt that is dynamically set according to the congestion status of the wireless section or the network 4 (hereinafter sometimes simply referred to as the network side). Based on the communication traffic.

  FIG. 2 is a diagram showing a general configuration relating to the token bucket of the wireless communication modem 2. The congestion status monitoring unit 201 detects the congestion status of the wireless section or the network 4 based on the effective throughput in the interface 210, for example. The token rate determination unit 202 determines the token rate Rt at the start timing of communication based on the detection result of the congestion state, and thereafter reviews the token rate Rt based on the effective throughput at a predetermined monitoring period.

  The token generation unit 203 generates a token 200 at the determined token rate Rt and outputs it to the token buffer 204. The reading unit 205 reads and transfers a predetermined amount of transmission / reception data 207 and 209 from the transmission buffer 206 or the reception buffer 208 every time one token 200 stored in the token buffer 204 is consumed.

  Since the congestion status monitoring unit 201 monitors the congestion status based on the throughputs of the transmission / reception data 207 and 209, the throughput is directly influenced by the token rate Rt as in the case where the token 200 is not accumulated in the token buffer 204. Under such circumstances, the congestion situation cannot be monitored accurately. Therefore, the token rate determining unit 202 determines and reviews the token rate only when the token 200 is sufficiently accumulated in the token buffer 204 and burst communication is possible.

  FIG. 3 is a block diagram showing a configuration relating to traffic control of the wireless terminal 1. The throughput detector 101 detects the throughput R0 of packets transmitted and received with the communication modem 2. The threshold value storage unit 102 stores in advance a threshold value Rref of the throughput R0 that can be estimated that the network side is congested. The comparison unit 103 compares the current throughput R0 with the threshold value Rref. When the throughput R0 falls below the threshold value Rref, the resource release request unit 104 requests the communication control unit 100 to release the radio resource.

  In response to the release request, the communication control unit 100 releases radio resources by appropriately disconnecting the physical layer and logical layer of the radio section. The release period determining unit 105 determines a release period Trelease of the radio resource. The resource acquisition unit 106 acquires the released radio resource again after the release period Trelease, establishes a session, and restarts radio communication.

  Next, the operation of the embodiment of the present invention will be described in detail with reference to the block diagram of FIG. 3 together with the flowchart and the time chart. FIG. 4 is a flowchart showing the operation of the first embodiment of the present invention, and mainly shows the operation of traffic control in the wireless terminal 1. FIG. 5 is a time chart thereof.

  In step S1, the throughput detector 101 detects the throughput R0 of the wireless terminal 1. The throughput R0 increases or decreases depending on the token rate Rt in the communication modem 2, and thus becomes an index representative of the wireless section and the congestion status of the network 4. In step S <b> 2, the comparison unit 103 compares the throughput R <b> 0 with a threshold value Rref stored in advance in the threshold value storage unit 102. If the throughput R0 exceeds the threshold value Rref as before time t1 in FIG. 5, it is determined that the token rate Rt in the communication modem 2 is high and that no serious congestion has occurred on the network side. Returning to S1, the above process is repeated.

  On the other hand, if the network side is congested and the token rate Rt of the communication modem 2 decreases and the throughput R0 falls below the threshold value Rref at time t1 in FIG. 5, this is detected in step S2 and the process proceeds to step S3. In step S3, the resource release request unit 104 notifies the communication control unit 100 of a radio resource release request in response to the comparison result.

  In response to this release request, the communication control unit 100 completely cuts off the communication, disconnects the physical link, reduces the session bandwidth of the wireless section, and disconnects the upper layer logical link, thereby The number of sessions connected to the station 3 is reduced. As a result, the deleted session band is allocated to another session in the radio section. In addition, since the wireless base station 3 has more vacant connection capacity, other wireless terminals can be newly accommodated. In step S <b> 4, the release period determining unit 105 determines a radio resource release period Trelease (here, Trelease <b> 1).

FIG. 6 is a flowchart showing an example of a method for determining the release period Trelease1 in step S4. In step S101, the current token rate Rt and token buffer size Mtb are read. In step S102, the token rate Rt and the token buffer size Mtb are applied to the following equation (1) to calculate the release period Trelease1.

Trelease1 ＝ Mtb / Rt… (1)

  Returning to FIG. 4, in step S5, it is determined whether or not the release period Trelease1 has elapsed since the release of the radio resource. If it is determined at time t2 in FIG. 5 that the release period Trelease1 has elapsed, the process proceeds to step S6, and a resource acquisition request is notified from the resource acquisition unit 106 to the communication control unit 100. The communication control unit 100 reconnects the released radio link and logical link in response to the resource acquisition request.

  In the above embodiment, it has been described that both the physical link and the logical link of the wireless communication are disconnected in order to release the wireless resource. However, the present invention is not limited to this, and the logical link is not limited to this. Only the physical link may be disconnected while maintaining the link, and only the session band in the wireless section may be released.

  According to the present embodiment, in wireless communication traffic control employing a token bucket algorithm, the wireless section and network are congested, the token rate decreases, and accordingly, the wireless communication throughput decreases. Wireless resources are temporarily released, then wireless resources are acquired again and wireless communication is resumed, so that sessions that cannot obtain high throughput due to network congestion can be prevented from occupying valuable wireless resources unnecessarily. It becomes like this.

  Further, when the network side is congested to release the radio resources, the session band occupied in the radio section can be released if only the physical link is disconnected while maintaining the logical link. Moreover, since the logical link is maintained, the wireless communication can be quickly resumed only by reconnecting the physical link.

  Further, if not only the physical link but also the logical link is disconnected in order to release the radio resource, the connection capacity of the radio base station can be released in addition to the release of the session band occupied in the radio section. Furthermore, since the burst communication becomes possible after the release period Trelease1, the token rate can be accurately reviewed.

  Even if the physical link as well as the logical link is disconnected in order to release the wireless resource, if the wireless terminal 1 or the opposing peer 5 has a resume function, the wireless communication is not interrupted. It will be possible to resume. Further, if the release period Trelease1 is notified to the upper layer of the wireless terminal 1, the upper layer can grasp the period during which no wireless communication is performed, so that the wireless communication function is set to the sleep state or the like only during the period. With this, power consumption can be reduced.

  FIG. 7 is a flowchart showing the operation of the second embodiment of the present invention, and FIG. 8 is a time chart thereof. Here again, the operation of this embodiment will be described by focusing on the traffic control operation in the wireless terminal 1.

  In step S11, the throughput detector 101 detects the throughput R0 in the token bucket algorithm of the wireless terminal 1. In step S <b> 12, the comparison unit 103 compares the throughput R <b> 0 with a threshold value Rref stored in advance in the threshold value storage unit 102. If the throughput R0 is higher than the threshold value Rref as before time t1 in FIG. 8, it is determined that the token rate Rt in the communication modem 2 is high and no congestion occurs on the network side, so step S11. The above processing is repeated after returning to step S2.

  On the other hand, when the token rate of the communication modem 2 decreases due to congestion on the network side and the throughput R0 falls below the threshold value Rref at time t1 in FIG. 8, this is detected in step S12 and proceeds to step S13. In step S13, the resource release request unit 104 notifies the communication control unit 100 of a resource release request in response to the comparison result. In response to this request, the communication control unit 100 reduces the session bandwidth in the wireless section by suppressing the throughput R0 to a regulated rate (shape plate) Rshape lower than the current token rate Rt. As a result, in the wireless section, a session bandwidth corresponding to the reduced session bandwidth is allocated to other sessions. In step S14, the release period determining unit 105 determines the release period Trelease (here, Trelease2) of the radio resource.

FIG. 9 is a flowchart showing an example of a method for determining the release period Trelease2 in step S14. In step S201, the current token rate Rt and token buffer size Mtb are read. In step S102, the token rate Rt, the regulation rate Rshape, and the token buffer size Mtb are applied to the following equation (2) to calculate the release period Trelease2.

Trelease2 ＝ Mtb / (Rt−Rshape)… (2)

  Returning to FIG. 7, in step S15, it is determined whether or not the release period Trelease2 has elapsed since the radio resource was released. When it is determined at time t2 that the release period Trelease2 has elapsed, the process proceeds to step S16, and a resource acquisition request is notified from the resource acquisition unit 106 to the communication control unit 100. The communication control unit 100 releases the restriction on the throughput in response to the resource acquisition request.

  According to this embodiment, when the network side is congested to release radio resources, the throughput is suppressed to a regulated rate lower than the throughput corresponding to the token rate while maintaining the logical link. Part of the session bandwidth occupied in the wireless section can be released. Therefore, the released session bandwidth can be allocated to other sessions. Further, since the regulation rate Rshape is set lower than the token rate Rt, the token buffer can be recovered. Therefore, after the end of the release period Trelease2, burst communication is possible, and the token rate can be accurately reviewed.

  In the second embodiment, the radio resource release period Trelease2 is predicted in advance, and then the throughput restriction is released after the elapsed time reaches the release period Trelease2. Not limited to this, when switching to communication at the regulated rate Rshape at the time t1 in response to a resource release request, the ratio according to the difference between the regulated rate Rshape and the token rate Rt (> Rshape) Focusing on the point that the token buffer gradually recovers, the timing at which the token buffer is completely recovered may be detected to cancel the throughput restriction.

  Such control of the third embodiment can be realized by changing the processing of steps S14 and S15 as shown in the flowchart of FIG.

  That is, in step S13 (time t1), in response to the resource release request, when the throughput regulation that suppresses the throughput to the rate Rshape lower than the token rate Rt is started, the token buffer size Mtb is read in step S51. In step S52, the total token amount M is reset. In step S53, the actual transfer amount m to the network side is measured every unit time ΔT.

  In step S54, the coefficient for converting the token rate Rt to the token amount is α (for example, α = 1), and the token amount α · Rt generated at the current token rate Rt is communicated at the current regulated rate Rshape. By subtracting the token amount m consumed, the token amount (α · Rt−m) accumulated in the token buffer is calculated every unit time ΔT, and the total token amount M is calculated as the token amount (α · Rt−m). ) Is added to the value. The consumed token amount m can be obtained from the transfer amount measured using a cumulative packet counter or the like.

  In step S55, it is determined whether or not the total token amount M has reached the token buffer size mtb. If not, the process returns to step S53. When the total token amount M reaches the token buffer size Mtb, the process proceeds to step S16, and the throughput restriction is released.

  According to this embodiment, when the network side is congested and throughput is reduced, the throughput is regulated to the regulation rate Rshape or less and a part of the physical link is released, while the token amount accumulated in the token buffer Is accurately detected based on the token rate and the actual transfer amount of the packet. Therefore, if the throughput restriction is canceled at the timing when the token buffer is sufficiently filled with tokens, there is no waste for the user because the token overflows from the token buffer and the transmission / reception opportunity is lost. As a result, it is possible to maximize the throughput regulation time as long as the profits are not impaired. Furthermore, since the burst communication becomes possible after the cancellation of the throughput regulation, the token rate can be accurately reviewed.

  In each of the above-described embodiments, it has been described that the throughput is regulated immediately when the throughput R0 falls below the threshold value Rref. However, even if the throughput R0 falls below the threshold value Rref, the total communication after the start of communication or the cancellation of the throughput regulation When the time is below a predetermined minimum guarantee time or the like (minimum guarantee condition), the throughput regulation may be started after the minimum guarantee time or the like has elapsed. Alternatively, until the total communication time reaches a predetermined minimum guarantee time or the like, the determination of whether or not to start the throughput regulation may be skipped.

  Further, when the total transfer amount is adopted instead of the total communication time and the total transfer amount after the start of communication or the throughput regulation is released is less than a predetermined minimum guaranteed transfer amount, the minimum guaranteed transfer amount Wait until it reaches the start of throughput regulation, or until the total transfer amount reaches a predetermined minimum guaranteed transfer amount, the determination of whether to start the throughput regulation may be skipped. good.

  DESCRIPTION OF SYMBOLS 1 ... Wireless terminal, 2 ... Wireless communication modem, 3 ... Wireless base station, 4 ... Communication network, 5 ... Opposing peer, 100 ... Communication control part, 101 ... Throughput detection part, 102 ... Threshold storage part, 103 ... Comparison part, 104 ... Resource release request unit, 105 ... Release period determination unit, 106 ... Resource acquisition unit

Claims (8)

In a traffic control device for radio communication in which traffic control by a token bucket algorithm is adopted for radio communication relaying a radio base station, and throughput is controlled according to a token rate,
Means for detecting communication throughput;
Means for comparing the throughput to a threshold estimated to be congested on the network side;
Means for releasing at least some of the occupied radio resources when the throughput is below the threshold;
Means for determining a release period of the radio resource;
A wireless communication traffic control apparatus comprising: means for reserving the released radio resource and restarting communication after elapse of the release period from the release of the radio resource.   The means for releasing the radio resource releases the session band occupied in the radio section by disconnecting the physical link while maintaining the logical link when the throughput falls below a threshold value. The wireless communication traffic control device according to 1.   The means for releasing the radio resource releases the connection capacity occupied by the radio base station by disconnecting the logical link together with the physical link when the throughput falls below a threshold value. A wireless communication traffic control device according to claim 1.   When the throughput falls below a threshold, the means for releasing the radio resource suppresses the throughput to a regulated rate lower than the token rate while maintaining a logical link, thereby reducing one of the session bandwidths occupied in the radio section. The wireless communication traffic control device according to claim 1, wherein the wireless communication traffic control device is released.   The wireless communication traffic according to claim 2 or 3, wherein the means for determining a release period of the radio resource determines a time required for the token buffer to become full at a current token rate as the release period. Control device.   6. The wireless communication traffic control apparatus according to claim 1, further comprising means for notifying the release period to an upper layer of a wireless terminal.   The means for releasing the radio resource does not release the radio resource until the total communication time or the total transfer amount satisfies a minimum guarantee condition even if the throughput falls below the threshold value. A wireless communication traffic control device according to any one of the above. In a traffic control method for wireless communication in which traffic control by a token bucket algorithm is adopted for wireless communication relaying a wireless base station, and throughput is controlled according to a token rate,
Detect communication throughput,
Comparing the throughput with a threshold estimated to be congested on the network side;
When the throughput falls below the threshold, release at least some of the occupied radio resources;
Determining a release period of the radio resource;
A radio communication traffic control method, wherein after the elapse of the release period from the release of the radio resource, the released radio resource is secured and communication is resumed.

Images