JP2014165542A - Radio communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radio communication device which can prevent transmission efficiency from degrading and also improve unfairness of throughput in uplink communication and downlink communication.SOLUTION: The radio communication device which operates as a base station 1 in a radio LAN communication system adopting a CSMA (Carrier Sense Multiple Access) method, comprises: a transmission buffer unit 12 which stores data received from a network; a frame aggregation unit 14 which aggregates a plurality of data frames to a terminal; and a communication control unit 16 which changes the number of data frames to be aggregated by the frame aggregation unit 14 on the basis of an amount of stored data in the transmission buffer unit 12.

Description

  The present invention improves the unfairness of throughput by controlling the rate of uplink and downlink throughput in a wireless LAN communication system, particularly a wireless LAN communication system based on CSMA (Carrier Sense Multiple Access) method. The present invention relates to a wireless communication apparatus.

  Hereinafter, a conventional wireless communication apparatus will be described. For example, when considering a usage pattern of a wireless LAN in an office in a company, a usage pattern in which a plurality of terminals (STAs) are connected to a single base station (AP: Access Point) is common. Used for. In this case, in the normal access operation in the CSMA scheme of the wireless LAN communication system, the transmission opportunities of one base station and one terminal are equal, so one terminal communicates with one base station. In this case, the throughput of uplink communication (base station ← terminal) and downlink communication (base station → terminal) will be the same, but if one base station and multiple terminals communicate simultaneously, uplink communication will be downlinked. Since there are more transmission opportunities than communication, there is a problem that upstream communication becomes dominant and throughput of downstream communication is suppressed. In order to avoid such a problem that the throughput of downlink communication is suppressed and to realize fair communication of uplink communication and downlink communication, QoS parameters (AIFS, CWmin specified in the wireless LAN standard IEEE802.11e) are used. , CWmax), a method using a parameter such as CWmin which is the minimum value of CW (CW: Contention Window, contention window) is considered (for example, see Patent Document 1).

Japanese Patent Laying-Open No. 2005-12725 (page 6)

  However, in the method for controlling CWmin and the like used in the conventional wireless communication apparatus, it is necessary to make the CWmin of the base station smaller than the CWmin of the terminal in order to prioritize downlink communication. If it is too small, the transmission signals of a plurality of terminals compete in a narrow contention window, resulting in an increase in frame collisions, resulting in a problem of reduced throughput. In order to give priority to downlink communication, conversely, a method of increasing the CWmin of uplink communication is conceivable. However, if this CWmin is excessively increased, the transmission interval of the transmission signal becomes long and the transmission efficiency deteriorates. As a result, there was a problem that the throughput was lowered.

  The present invention has been made in view of the above, and it is an object of the present invention to obtain a wireless communication apparatus capable of improving the unfairness of uplink communication and downlink communication throughput while preventing deterioration in transmission efficiency. Objective.

  In order to solve the above-described problems and achieve the object, the present invention is a wireless communication apparatus that operates as a base station of a wireless LAN communication system to which the CSMA method is applied, and stores data received from the network side. Means, aggregation means for aggregating a plurality of data frames addressed to the terminal, and control means for changing the number of data frames aggregated by the aggregation means based on the amount of data accumulated in the accumulation means. Features.

  According to the present invention, it is possible to control the throughput ratio between uplink communication and downlink communication, and it is possible to improve the unfairness of the throughput of uplink communication and downlink communication.

FIG. 1 is a diagram illustrating a configuration example of Embodiment 1 of a base station and a terminal which are wireless communication devices. FIG. 2 is a diagram illustrating an example of an operation sequence of the base station and the terminal according to the first embodiment. FIG. 3 is a diagram illustrating an example of a setting table for the number of AP aggregations according to the first embodiment. FIG. 4 is a diagram illustrating a theoretical calculation result of the throughput characteristic of the first embodiment. FIG. 5 is a diagram illustrating a configuration example of a base station and a terminal according to the second embodiment. FIG. 6 is a diagram illustrating an example of an operation sequence of the base station and the terminal according to the second embodiment. FIG. 7 is a diagram illustrating an example of a setting table for the number of AP aggregations according to the second embodiment. FIG. 8 is a diagram illustrating a theoretical calculation result of the throughput characteristics of the second embodiment. FIG. 9 is a diagram illustrating a configuration example of a base station and a terminal according to the third embodiment. FIG. 10 is a diagram illustrating an example of an operation sequence of the base station and the terminal according to the third embodiment. FIG. 11 is a diagram illustrating an example of an AP reception buffer size setting table according to the third embodiment.

  Embodiments of a wireless communication apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a base station (AP) and a terminal (STA) which are wireless communication apparatuses according to the present invention. As shown in FIG. 1, a plurality of terminals 2 (terminals 2 ₁ , 2 ₂ ,..., 2 _n ) are connected to the base station 1. A communication system including the base station 1 and the terminal 2 is a wireless LAN communication system based on the CSMA method.

  The base station 1 is a wireless communication device that measures the amount of downlink communication traffic, changes the number of frame aggregations based on the amount of traffic, and controls the ratio of uplink communication and downlink communication throughput.

  As shown in FIG. 1, the base station (AP) 1 includes a data distribution unit 11, a transmission buffer unit 12, a queuing unit 13, a frame aggregation unit 14, a transmission / reception unit 15, a communication control unit 16, and a reception buffer 17. It has. The base station 1 transmits data received from the network side to the terminal 2 and transmits data received from the terminal 2 to the network side.

The data distribution unit 11 distributes the data transmitted from the network side to a transmission buffer prepared for each of the n terminals 2. The transmission buffer unit 12 includes n transmission buffers 12 _{1 to} 12 _n for storing data allocated to the STA (1) to STA (n), which are n terminals 2 in the data distribution unit 11. Become. The queuing unit 13 extracts data stored in each transmission buffer in the transmission buffer unit 12 according to a rule such as round robin. The frame aggregation unit 14 aggregates a plurality of frames extracted from the transmission buffer unit 12 based on the control information from the communication control unit 16. The transmission / reception unit 15 modulates and transmits the frame after frame aggregation output from the frame aggregation unit 14 and demodulates the received frame. The communication control unit 16 measures the data accumulation amount of the transmission buffer unit 12 and controls the number of aggregations of the frame aggregation unit 14 according to the data accumulation amount. The reception buffer 17 stores the data received and demodulated by the transmission / reception unit 15.

  Each terminal (STA) 2 has the same configuration, and includes a transmission buffer 21, a frame aggregation unit 22, a transmission / reception unit 23, a communication setting unit 24, and a reception buffer 25. The terminal 2 receives a transmission signal from the base station 1 and transmits a signal to the base station 1.

  The transmission buffer 21 accumulates transmission data to the base station 1. The frame aggregation unit 22 aggregates a plurality of frames output from the transmission buffer 21. The transmission / reception unit 23 modulates and transmits the frames aggregated by the frame aggregation unit 22 and demodulates the received frames. The communication setting unit 24 sets the number of frame aggregations in the frame aggregation unit 22 according to the notification from the base station 1 or the like. The reception buffer 25 stores the data received and demodulated by the transmission / reception unit 23.

Next, the operation will be described. First, the data received from the network side in the base station 1 is distributed by the data distribution unit 11 to the transmission buffers 12 _{1 to} 12 _n in the transmission buffer unit 12 prepared for each of the n terminals 2. The transmission buffer unit 12 stores the data allocated to the n terminals 2 by the data distribution unit 11 in the n transmission buffers 12 _{1 to} 12 _n . The queuing unit 13 extracts data from the transmission buffers 12 _{1 to} 12 _n prepared for each of the n terminals 2 (STA (1) to STA (n)) according to a rule such as round robin. The data extracted from the queuing unit 13 is aggregated into a plurality of frames by the frame aggregation unit 14. The number of aggregations set by the frame aggregation unit 14 is determined from a measurement amount obtained by measuring the data accumulation amount of the transmission buffer unit 12 by the communication control unit 16. The frames aggregated by the frame aggregation unit 14 are modulated by the transmission / reception unit 15 and transmitted as a radio signal.

On the other hand, in the terminals 2 _{1 to} 2 _n , the radio signal transmitted from the base station 1 is received and demodulated by the transmission / reception unit 23, and the demodulated data is stored in the reception buffer 25. The transmission data is temporarily stored in the transmission buffer 21. The frame aggregation unit 22 extracts transmission data stored in the transmission buffer 21 at a predetermined timing, and aggregates (aggregates) it into a plurality of frames. The number of aggregations set by the frame aggregation unit 22 is determined by the communication setting unit 24 based on information notified from the base station 1 or the like. The frames aggregated by the frame aggregation unit 22 are modulated by the transmission / reception unit 23 and transmitted as a radio signal.

  FIG. 2 is a diagram illustrating an example of an operation sequence of the base station 1 and the terminal 2 according to the first embodiment. In the present embodiment, in step S100, each terminal (STA) first establishes an association with the base station (AP). Next, in step S101, the AP determines an initial value of the number of aggregations based on information on the number of STAs associated with the AP. The initial value is determined by the communication control unit 16. The communication control unit 16 sets the determined initial value in the frame aggregation unit 14 and notifies the STA of the initial value. In the STA notified of the initial value of the aggregation number, the communication setting unit 24 sets the initial value of the aggregation number in the frame aggregation unit 22. Next, in step S102, the AP and the STA aggregate a plurality of transmission frames according to the set number of aggregations and transmit data. At this time, the communication control unit 16 of the AP constantly measures the amount of downlink communication traffic (hereinafter referred to as the amount of downlink traffic) from the amount of data stored in the transmission buffer unit 12. Also, the necessity of changing the number of aggregations is determined from the measurement result of the downlink traffic volume. If it is determined that the number of aggregations needs to be changed, step S103 is executed to change the number of aggregations in itself (AP). For example, as shown in the example of the AP aggregation number setting table in FIG. 3, when it is assumed that the amount of data in the transmission buffer in the AP has increased and the amount of downlink traffic has increased, the throughput of downlink communication is increased. Therefore, a setting is made to increase the number of AP aggregations. On the other hand, when it is assumed that the amount of data in the transmission buffer in the AP has decreased and the amount of downlink communication traffic has decreased, a setting is made to reduce the number of AP aggregations in order to reduce the throughput of downlink communication. For example, if the number of associated STAs is N2, if the amount of data in the transmission buffer in the AP is greater than or equal to X1 and less than X2, the number of aggregations is set to B1, and then the aggregation is performed when the amount of data in the transmission buffer reaches X2. Change the number setting to B2. When the number of aggregations is changed according to the table of FIG. 3, the number of aggregations in the STA frame aggregation unit 22 is fixed to S2. Of course, the number of aggregations in the STA frame aggregation unit 22 may be variable. In step S104, the AP and the STA perform data transmission by aggregating a plurality of transmission frames according to the number of aggregations whose settings have been changed. Thereafter, when the aggregation number needs to be changed, the setting of the aggregation number is changed in the same procedure.

  FIG. 4 shows that when 10 STAs simultaneously communicate with one AP in the wireless LAN standard of IEEE802.11n (MCS15 [2 streams, 20 MHz band]), the CWmin of the AP and STA is set to 15, respectively. This is a theoretical calculation result of the throughput characteristics when the number of aggregations (uplink aggregation number) is fixed at 5 and the AP aggregation number (downlink aggregation number) is changed. As shown in FIG. 4, the rate of uplink communication and downlink communication throughput can be changed by variably controlling the number of AP aggregations in accordance with the amount of data in the transmission buffer in the AP. Thus, it is possible to control the throughput such as improving the downlink communication throughput by suppressing the throughput.

  Thus, in this Embodiment, it was set as the structure which controls the number of aggregation of a base station and a terminal according to the data amount in the transmission buffer of a base station. Thereby, it becomes possible to control the ratio of the throughput of uplink communication and downlink communication, and to improve the unfairness of the throughput of uplink communication and downlink communication. Since only the number of aggregations is changed, transmission efficiency is not deteriorated.

Embodiment 2. FIG.
FIG. 5 is a diagram illustrating a configuration example of the base station (AP) 1b and the terminal (STA) 2b (terminals 2b ₁ , 2b ₂ ,..., 2b _n ) according to the second embodiment. The base station 1b replaces the communication control unit 16 of the base station 1 (see FIG. 1) of the first embodiment with the communication control unit 16b, and adds a CW control unit 18 between the frame aggregation unit 14 and the transmission / reception unit 15. It has a configuration. Constituent elements common to the base station 1 are denoted by the same reference numerals. The terminal 2b has a configuration in which the communication setting unit 24 of the terminal 2 of the first embodiment is replaced with a communication setting unit 24b, and a CW control unit 26 is added between the frame aggregation unit 22 and the transmission / reception unit 23. . Constituent elements common to the terminal 2 are denoted by the same reference numerals. In this embodiment, parts different from those in Embodiment 1 will be described.

  In the base station 1b, the communication control unit 16b measures the data accumulation amount of the transmission buffer unit 12, and in accordance with the data accumulation amount, the number of aggregations of the frame aggregation unit 14 and the QoS parameters (AIFS, AIFS, CW control unit 18). CWmin, CWmax). The CW control unit 18 controls a value such as CWmin in the QoS parameter based on the control information from the communication control unit 16b.

  In the terminal 2b, the communication setting unit 24b sets the number of frame aggregations in the frame aggregation unit 22 and the QoS parameters of the CW control unit 26 in accordance with the notification from the base station 1b. The CW control unit 26 controls a value such as CWmin in the QoS parameter based on the control information of the communication setting unit 24b.

Next, the operation will be described. First, the data received from the network side in the base station 1b is distributed by the data distribution unit 11 to the transmission buffers 12 _{1 to} 12 _n in the transmission buffer unit 12 prepared for each of the n terminals 2b. The transmission buffer unit 12 stores the data distributed to the n terminals 2b by the data distribution unit 11 in the n transmission buffers 12 _{1 to} 12 _n . The queuing unit 13 extracts data from the transmission buffers 12 _{1 to} 12 _n prepared for each of the n terminals 2b (STA (1) to STA (n)) according to rules such as round robin. The data extracted from the queuing unit 13 is aggregated into a plurality of frames by the frame aggregation unit 14. The aggregated frame output from the frame aggregation unit 14 is adjusted in frame transmission timing by the CW control unit 18 controlling a value such as CWmin. The number of aggregations set by the frame aggregation unit 14 and the values such as CWmin set by the CW control unit 18 are determined from the measurement amount obtained by measuring the data accumulation amount of the transmission buffer unit 12 in the communication control unit 16b. The frame whose transmission timing is adjusted by the CW control unit 18 is modulated by the transmission / reception unit 15 and transmitted as a radio signal.

On the other hand, in the terminals 2b _{1 to} 2b _n , the radio signal transmitted by the base station 1b is received and demodulated by the transmission / reception unit 23, and the demodulated data is stored in the reception buffer 25. The transmission data is temporarily stored in the transmission buffer 21. The frame aggregation unit 22 extracts transmission data stored in the transmission buffer 21 at a predetermined timing, and aggregates (aggregates) it into a plurality of frames. The frames aggregated by the frame aggregation unit 22 are controlled by the CW control unit 26 such as the value of CWmin and the frame transmission timing is adjusted. The communication setting unit 24b determines the number of aggregations set by the frame aggregation unit 22 and the QoS values such as CWmin set by the CW control unit 26 based on information notified from the base station 1b. The frame whose transmission timing is adjusted by the CW control unit 26 is modulated by the transmission / reception unit 23 and transmitted as a radio signal.

  FIG. 6 is a diagram illustrating an example of an operation sequence of the base station 1b and the terminal 2b according to the second embodiment. In the present embodiment, in step S200, each terminal (STA) first establishes an association with the base station (AP). Next, in step S201, the AP determines an initial value of the number of aggregations based on information on the number of STAs associated with the AP. In the AP, the communication control unit 16b determines an initial value of the number of aggregations, sets the determined initial value in the frame aggregation unit 14, and notifies the STA of the initial value. In the STA notified of the initial value of the aggregation number, the communication setting unit 24 b sets the initial value of the aggregation number in the frame aggregation unit 22. Further, in step S202, the communication control unit 16b determines a CWmin value based on the information on the number of STAs associated with the communication control unit 16b, sets the determined CWmin value in the CW control unit 18, and sets the determined CWmin value in the STA. Notice. In the STA notified of the CWmin value, the communication setting unit 24b sets the CWmin value in the CW control unit 26. In step S203, the AP and the STA perform transmission data aggregation by performing aggregation of transmission frames and adjustment of transmission timing according to the set number of aggregations and CWmin. At this time, the communication control unit 16b of the AP always measures the downlink traffic amount from the data accumulation amount of the transmission buffer unit 12. Also, the necessity of changing the number of aggregations is determined from the measurement result of the downlink traffic volume. If it is determined that the number of aggregations needs to be changed, step S204 is executed to change the number of aggregations in itself (AP). For example, as shown in the example of the AP aggregation number setting table in FIG. 7, when it is assumed that the amount of data in the transmission buffer in the AP has increased and the amount of downlink communication traffic has increased, the throughput of downlink communication is increased. Therefore, a setting is made to increase the number of AP aggregations. In step S205, the AP and the STA perform data transmission by aggregating a plurality of transmission frames according to the number of aggregations whose settings have been changed. Thereafter, when the aggregation number needs to be changed, the setting of the aggregation number is changed in the same procedure. Here, the number of aggregations is adjusted based on the traffic amount (the amount of data stored in the transmission buffer unit 12). However, in addition to the number of aggregations, QoS parameters such as CWmin may be adjusted together.

  FIG. 8 shows that when 10 STAs simultaneously communicate with one AP in the wireless LAN standard of IEEE802.11n (MCS15 [2 streams, 20 MHz band]), the CWmin of the AP and the STA is 7 and 15, respectively. 4 is a theoretical calculation result of throughput characteristics when the number of STA aggregations (uplink aggregations) is fixed to 5 and the AP aggregation number (downlink aggregations) is changed. As shown in FIG. 8, the ratio of uplink communication and downlink communication throughput can be changed with a smaller number of AP aggregations by variably controlling the number of AP aggregations according to the amount of data in the transmission buffer in the AP. Thus, it is possible to control the throughput such as improving the throughput of the downlink communication by suppressing the throughput of the uplink communication.

  Thus, in this Embodiment, it was set as the structure which can control QoS parameters, such as the number of aggregation of a base station and a terminal, and CWmin according to the data amount in the transmission buffer of a base station. Thereby, it becomes possible to control the ratio of the throughput of the uplink communication and the downlink communication with a smaller number of aggregations of the base station, and to improve the unfairness of the throughput of the uplink communication and the downlink communication. Also, by combining CW parameter control and frame aggregation variable control, it becomes possible to control the ratio of the throughput of uplink communication and downlink communication without reducing the value of CWmin so much, and by reducing CW The influence of frame collision can be reduced.

Embodiment 3 FIG.
In the first and second embodiments, the wireless communication apparatus has been described that uses the frame aggregation technique to control the ratio of the throughput of the uplink communication and the downlink communication to improve the unfairness of the throughput. It is possible to control the ratio of the uplink communication and the downlink communication throughput even by using the Block Ack method defined in .11e and part of the 802.11n standard.

FIG. 9 is a diagram illustrating a configuration example of the base station (AP) 1c and the terminal (STA) 2c (terminals 2c ₁ , 2c ₂ ,..., 2c _n ) according to the third embodiment. The base station 1c has a configuration in which the communication control unit 16 of the base station 1 (see FIG. 1) of the first embodiment is replaced with a communication control unit 16c, and the frame aggregation unit 14 is replaced with a block acknowledgment control unit 19. . Constituent elements common to the base station 1 are denoted by the same reference numerals. The base station 1c is a wireless communication device that measures the amount of downlink communication traffic, changes the reception buffer size in the block acknowledgment method based on the amount of traffic, and controls the throughput ratio between uplink communication and downlink communication.

  Further, the terminal 2c has a configuration in which the communication setting unit 24 of the terminal 2 of the first embodiment is replaced with the communication setting unit 24c, and the frame aggregation unit 22 is replaced with the block ack control unit 27. Constituent elements common to the terminal 2 are denoted by the same reference numerals. In this embodiment, parts different from those in Embodiment 1 will be described.

  In the base station 1c, the communication control unit 16c measures the data accumulation amount of the transmission buffer unit 12, and controls the reception buffer size according to the data accumulation amount. In addition to notifying the terminal 2c of the reception buffer size, the block acknowledgment controller 19 controls the number of consecutive frames sent based on the reception buffer size notified from the terminal 2c. The block acknowledgment control unit 19 controls block acknowledgment based on the control information from the communication control unit 16c.

  In the terminal 2c, the communication setting unit 24c sets the reception buffer size. In addition, the set reception buffer size is notified to the base station, and the number of frame transmissions in the block acknowledgment control unit 27 is set based on the reception buffer size notified from the base station. The block acknowledgment control unit 27 controls block acknowledgment based on the control information from the communication setting unit 24c.

Next, the operation will be described. First, the data received from the network side in the base station 1c is distributed by the data distribution unit 11 to the transmission buffers 12 _{1 to} 12 _n in the transmission buffer unit 12 prepared for each of the n terminals 2c. The transmission buffer unit 12 stores the data distributed to the n terminals 2c by the data distribution unit 11 in the n transmission buffers 12 _{1 to} 12 _n . The queuing unit 13 extracts data from the transmission buffers 12 _{1 to} 12 _n prepared for each of the n terminals 2c (STA (1) to STA (n)) according to a rule such as round robin. The data extracted from the queuing unit 13 is collected as a plurality of frames transmitted continuously by the block acknowledgment control unit 19. The number of frames to be continuously transmitted is set by the communication control unit 16c based on the reception buffer size notified from the terminal 2c. The plurality of frames output and transmitted continuously by the block acknowledgment control unit 19 are modulated by the transmission / reception unit 15 and transmitted as radio signals. The value of the reception buffer size in the base station 1c is determined from a measured amount obtained by measuring the data accumulation amount of the transmission buffer unit 12 in the communication control unit 16c. When determining the reception buffer size, the communication control unit 16c notifies the value to the terminal 2c.

On the other hand, the terminal 2c ₁ ~2c _n, a radio signal transmitted by the base station 1c is demodulated are received by the transceiver 23, the demodulated data is stored in the receiving buffer 25. The transmission data is temporarily stored in the transmission buffer 21. The block acknowledgment control unit 27 collects the data extracted from the transmission buffer 21 into a plurality of frames to be continuously transmitted. The communication frame setting unit 24c determines the number of consecutive frames set by the block acknowledgment control unit 27 based on the reception buffer size of the base station 1 notified from the base station 1. The frame continuously transmitted by the block acknowledgment control unit 27 is modulated by the transmission / reception unit 23 and transmitted as a radio signal.

  FIG. 10 is a diagram illustrating an example of an operation sequence of the base station 1c and the terminal 2c according to the third embodiment. In the present embodiment, in step S300, first, each terminal (STA) establishes an association with the base station (AP). Next, in step S301, the AP determines an initial value of the reception buffer size based on information on the number of STAs associated with the AP. In the AP, the communication control unit 16c determines an initial value of the reception buffer size, sets the determined initial value, and notifies the STA of the initial value. In the STA notified of the initial value of the reception buffer size in the AP, the communication setting unit 24c determines the number of consecutive transmission frames based on the notified initial value (reception buffer size). Is set in the block acknowledgment control unit 27. The communication setting unit 24c also determines and sets an initial value of its own reception buffer size and notifies the AP of the determined initial value. In the AP that is notified of the initial value of the reception buffer size in the STA, the communication control unit 16c determines the number of continuous transmission frames based on the notified initial value, and the determined number of continuous transmissions is determined by the block acknowledgment control unit 19. Set to. In the next step S302, the AP transmits data while controlling the number of consecutive transmission frames based on the reception buffer size of the STA notified from the STA. Further, the STA transmits data while controlling the number of transmission frames continuously based on the reception buffer size of the AP notified from the AP. At this time, the communication control unit 16c of the AP always measures the downlink traffic amount from the data accumulation amount of the transmission buffer unit 12. Also, the necessity of changing the reception buffer size is determined from the measurement result of the downlink traffic amount. If it is determined that the reception buffer size needs to be changed, step S303 is executed to change the reception buffer size in itself (AP). For example, as shown in the example of the AP reception buffer size setting table in FIG. 11, when it is assumed that the amount of data in the transmission buffer in the AP has increased and the traffic volume of downlink communication has increased, the reception buffer size of the AP is By making the setting to be reduced, the throughput of uplink communication transmitted by the STA is reduced. As a result, the throughput of downlink communication increases. On the other hand, if it is assumed that the amount of data in the transmission buffer in the AP has decreased and the amount of traffic in downlink communication has decreased, the throughput of uplink communication transmitted by the STA can be reduced by setting the AP reception buffer size to be large. Enlarge. Along with this, the throughput of downlink communication becomes small. In the AP, when the reception buffer size is changed, the communication control unit 16c notifies the STA of the changed reception buffer size. In the received STA, the communication setting unit 24c determines the received buffer size based on the notified reception buffer size. Thus, the continuous transmission number of transmission frames is re-determined, and the re-determined continuous transmission number is reset in the block acknowledgment control unit 27. In step S304, the AP and the STA transmit data while controlling the number of transmission frames continuously based on the reception buffer size on the reception side. Thereafter, when the reception buffer size needs to be changed, the setting of the reception buffer size is changed in the same procedure.

  Thus, in the present embodiment, the base station reception buffer size is controlled in accordance with the amount of data in the base station transmission buffer, and the number of consecutive transmission frames of the terminal in the block-ack scheme is controlled. . As a result, as in the first and second embodiments using the frame aggregation technique, it becomes possible to control the throughput ratio between the uplink communication and the downlink communication, thereby reducing the unfairness of the throughput between the uplink communication and the downlink communication. Can be improved.

  As described above, the wireless communication apparatus according to the present invention is suitable for a master station apparatus of a wireless LAN communication system to which the CSMA method is applied.

1, 1b, 1c base station _{(AP), 2 1 ~2 n} , 2b 1 ~2b n, 2c 1 ~2c n terminal (STA), 11 data distribution unit, 12 transmission buffer section, 12 ₁ to 12 _n, 21 transmission buffer, 13 queuing unit, 14, 22 frame aggregation unit, 15, 23 transmission / reception unit, 16, 16b, 16c communication control unit, 17, 25 reception buffer, 18, 26 CW control unit, 19, 27 blocks ACK control unit, 24, 24b, 24c Communication setting unit.

Claims (5)

A wireless communication apparatus that operates as a base station of a wireless LAN communication system to which a CSMA method is applied,
Storage means for storing data received from the network side;
An aggregation means for aggregating a plurality of data frames addressed to the terminal;
Control means for changing the aggregate number of data frames by the aggregation means based on the amount of data stored in the storage means;
A wireless communication apparatus comprising:   The wireless communication apparatus according to claim 1, wherein the control unit determines an aggregation number of data frames in the terminal based on the accumulation amount, and notifies the terminal of the determined aggregation number. Transmission timing adjustment means for adjusting the transmission timing of frames aggregated by the aggregation means;
Further comprising
The wireless communication apparatus according to claim 1, wherein the control unit changes a transmission timing adjustment amount used by the transmission timing adjustment unit based on the accumulation amount.   The wireless communication apparatus according to claim 3, wherein the control unit determines an adjustment amount of a frame transmission timing in the terminal based on the accumulation amount, and notifies the determined adjustment amount to the terminal. Applying the CSMA method, each device is a wireless communication device that operates as a base station of a wireless LAN communication system that continuously transmits a plurality of data frames based on a reception buffer size of a communication partner,
Storage means for storing data received from the network side;
Block acknowledgment control means for continuously sending a plurality of data frames addressed to the terminal in a batch according to the reception buffer size of the terminal;
A control means for changing the size of the reception buffer for storing the received data frame from the terminal based on the amount of data stored in the storage means, and for notifying the terminal of the changed reception buffer size;
A wireless communication apparatus comprising:

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