JP4137764B2 - Radio base station apparatus and transmission data control method - Google Patents

Description

  The present invention provides a multi-rate control compatible radio base station apparatus capable of using a plurality of transmission rates when transmitting a data frame to a subordinate radio terminal, and a data frame transmitted by the radio base station. The present invention relates to a transmission data control method for controlling a transmission rate.

  IEEE (Institute of Electrical and Electronic Engineers) is a multi-rate wireless communication system that dynamically switches the transmission rate between the wireless base station and the wireless terminal according to the communication environment between the wireless base station and the wireless terminal. An IEEE 802.11 system defined by the 802.11 committee has been known (see Non-Patent Document 1).

  In this IEEE 802.11 system, CSMA / CA (Carder Sense Multiple Access with Collision Avoidance) is defined as an access control procedure, and DCF (Distributed Coordinated Function) is defined as one of these procedures. Yes. DCF is a procedure in which each wireless terminal transmits and receives data while performing carrier sensing so that a frame collision does not occur when a plurality of wireless terminals and one wireless base station perform data transmission and reception.

FIG. 9 is a diagram showing a procedure of radio access control by DCF. In the figure, a radio access procedure in each apparatus when a data frame is transmitted from the radio terminals 201, 202, 203 to the radio base station 100 is shown.
Here, in the T1 section, each of the wireless terminals 201, 202, and 203 performs carrier sense on the DIFS (DCF Interframe Space) and the Backoff time given to itself, If 100 channels are idle, a data frame is transmitted to the radio base station 100.

Here, since the Backoff time of the wireless terminal 201 is the shortest among the wireless terminals 201, 202, and 203, the wireless terminal 201 transmits the data frame D1 after performing carrier sense. After waiting for SIFS (Short Interframe Space) time, the radio base station 100 transmits an ACK frame, which is an acknowledgment to the data frame D1, to the radio terminal 201 and completes communication.
Next, in the T2 section, the wireless terminal 202 and the wireless terminal 203 perform Backoff control of the Backoff time carried over in the T1 section after waiting for the DIFS time. Here, the Backoff time is determined by a random value within a certain interval.

Specifically, the Backoff time is obtained by the following calculation formula.
Backoff time = DIFS + CW / 2 x Slottime
(DIFS; minimum transmission waiting time required for data frame transmission, CW (Contention Window); parameter for determining transmission waiting time determined according to the number of retransmissions when colliding with a packet. In the range from 0 to CW within a specified range, a uniformly distributed parameter is generated, and CW is determined between 15 (CWmin: minimum CW) and 1023 (CWmax: maximum CW), and is retransmitted. Slottime, which increases exponentially every time, is a fixed time in which the random number value determined by CW is decreased, and the random number value is decreased at each slottime, and the wireless terminal that first becomes 0 transmits data (The reason why CW / 2 is used in the above calculation formula is that CW / 2 is determined as an average of random values of the wireless terminals.)

  In the example shown in FIG. 9, since the random number values given to the wireless terminal 202 and the wireless terminal 203 match, both the wireless terminals 202 and 203 transmit the data frames D2 and D3 at the same time, and the data frame D2 , D3 occurs. When a collision occurs, the radio base station 100 does not transmit an ACK frame, so that the radio terminal 202 and the radio terminal 203 perform a data frame retransmission procedure.

  Finally, in the T3 section, the wireless terminal 202 and the wireless terminal 203 set the Backoff time again. At the time of retransmission, the probability of re-collision in simultaneous transmission is reduced by expanding the range of CW exponentially. Here, as shown in FIG. 9, since the Backoff time of the wireless terminal 202 is shorter than the Backoff time of the wireless terminal 203, the wireless terminal 202 transmits a data frame after carrier sense, and from the wireless base station 100. The ACK frame is received and communication is completed. Each time successive retransmissions are repeated, the CW range is expanded and the probability of re-collision is reduced.

  According to the IEEE 802.11 standard, in one-to-one communication between one radio base station and one radio terminal, the radio base station or radio terminal that transmitted the data frame is the radio base station that is the transmission destination. Alternatively, when an ACK frame, which is an acknowledgment to the data frame, is received from the wireless terminal, the data frame has been successfully transmitted. If the ACK data cannot be received due to a data frame collision or the like, Frame transmission failure.

Next, FIG. 10 shows an example of a communication procedure by conventional multi-rate control. The figure shows a multi-rate control procedure in each device when data frames are transmitted and received between the radio base station 100 and the radio terminals 201, 202, and 203.
Here, it is assumed that the transmission rate of the data frame from the wireless terminals 201, 202, 203 to the wireless base station 100 can be selected from a plurality of transmission rates R1, R2, R3.

  As shown in the figure, the data frames D11 to D13 addressed from the wireless terminal 201 to the wireless base station 100 are normally received by the wireless base station 100. For this reason, the radio base station 100 transmits an ACK frame for each of the received data frames D11, D12, and D13 to the radio terminal 201. That is, this state indicates that the transmission of the data frame has been continuously successful.

Here, since the wireless terminal 201 has succeeded in data transmission continuously from the data frame D11 to the data frame D13, the data transmission rate of the data frame D14 is higher than the transmission rate R2 up to the data frame D13. Transmission is performed at the transmission rate R1, which is the rate.
This is because the data frame D11 is transmitted continuously from the data frame D11 to the data frame D13, and therefore the data frame D14 is transmitted at a higher transmission rate R1, thereby reducing the data transmission time and the wireless network. This is to improve the transmission efficiency in the network.

Next, the wireless terminal 202 transmits data frames from the data frame D21 to the data frame D23 to the wireless base station 100, and an ACK frame is received from the wireless base station 100 for the data frame D22. Not received. In this case, the data frame D22 indicates that transmission of the data frame has failed.
Therefore, the wireless terminal 202 generates and transmits a data frame D23 that includes data having the same contents as the data frame D22 for which transmission has failed, and in which a Retry bit indicating retransmission is set in the header.

Since the wireless terminal 202 has received the ACK frame from the wireless base station 100 for the retransmission data frame D23, the wireless terminal 202 determines that the transmission is successful and transmits the next data frame D24 as usual.
Finally, the wireless terminal 203 transmits a continuous data frame from the data frame D31 to the data frame D34 to the wireless base station 100. As for the data frame D31, since the ACK frame is not transmitted from the radio base station 100 to the radio terminal 202, the radio terminal 203 determines that the data transmission has failed and transmits the data frame D32 that is a retransmission frame. Further, since the ACK frame is not transmitted for the data frame D33, the wireless terminal 203 determines that the data transmission has failed.

Here, since the wireless terminal 203 continuously fails to transmit data from the data frame D31 to the data frame D33, the transmission rate for the data frame D34 is from the data frame D31 to the data frame D33. Transmission is performed at a transmission rate R3, which is slower than R2.
This is because transmission from frame D31 to frame D33 has failed continuously, so frame D34 is transmitted at a lower transmission rate to ensure that it reaches radio base station 100, and the probability of retransmission of data frames is reduced. This is to improve the transmission efficiency in the wireless network.

In the above description, the multi-rate control when data frames are transmitted from the wireless terminals 201, 202, and 203 to the wireless base station 100 has been described. However, data is transmitted from the wireless base station 100 to the wireless terminals 201, 202, and 203. When transmitting a frame, the radio base station 100 performs multi-rate control similar to that of the radio terminals 201, 202, and 203.
As described above, in the conventional multi-rate control, the transmission rate between the radio base station and the radio terminal is determined by the communication environment, and the communication environment between the radio base station and the radio terminal is poor. While transmission / reception is performed at a low transmission rate, transmission / reception is performed at a high transmission rate when the communication environment between the wireless base station and the wireless terminal is good, thereby improving the efficiency of data transmission in the wireless section. It was.

Also, by setting the priority when transmitting data frames according to the data frame transmission rate determined by the communication environment, throughput is improved and high performance of the entire wireless communication network is realized. A technique for this is disclosed (for example, Patent Document 1).
IEEE Std 802.11: “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification”, IEEE, Nov, 1999. JP 2003-110575 A (summary)

However, in wireless communication such as wireless LAN (Local Area Network) communication, the wireless terminal can move, so depending on the distance between the wireless terminal and the wireless base station and the installation position of the wireless terminal. The environment varies greatly.
Therefore, in the conventional method of determining the transmission rate only in the communication environment, the transmission rate frequently changes depending on the communication environment of the wireless terminal. Therefore, the fluctuation of the transmission delay time of the data frame between the wireless terminal and the wireless base station There is a drawback that it is difficult to transmit and receive data frames at a stable transmission rate.

  In addition, in the conventional multi-rate control, the purpose is to achieve high throughput in data communication as in Patent Document 1, but in real-time communication, data / data is transmitted at regular intervals rather than realizing high throughput. It is important to transmit the frame without error. For this reason, the conventional multi-rate control method has a problem that it is less effective for improving the communication quality of real-time data such as voice data.

Furthermore, transmission rate determination by multi-rate control is performed individually at each radio terminal and radio base station, and the radio base station monitors the transmission status of the entire radio terminals under its control and performs optimal transmission. The rate could not be determined.
Here, when an increase in traffic in the radio section occurs, when a data frame is transmitted / received between the radio base station and the radio terminal, it collides with a data frame transmitted / received by another radio terminal. The possibility increases. Further, when a data frame collision occurs, an ACK frame, which is an acknowledgment to the transmission data frame, is not transmitted to the data transmission side device, so the data transmission side device determines that there is a packet loss, Retransmit data frame.

At this time, in order to reduce the probability of re-collision of data frames, the Backoff time increases exponentially with each retransmission. At this time, if the transmission rate of the data frame is lowered, the collision probability of the packet is further increased, and when the data frame collides again, a vicious cycle occurs in which the transmission waiting time is further increased.
As described above, in the conventional multirate control method in which the data frame transmission rate is determined only in the communication environment between the radio terminal and the radio base station apparatus, communication between the radio terminal and the radio base station apparatus is performed. It has been difficult to maintain a certain communication quality due to the fact that the environment changes frequently and the transmission rate decreases due to data frame collision when the total traffic volume increases.
The present invention has been made in view of the above-described problems. In a multi-rate compatible wireless communication system, a wireless base station apparatus for efficiently performing data transmission and maintaining constant transmission quality, and transmission data It aims to provide a control method.

  In order to solve the above problem, the invention according to claim 1 is a multi-rate compatible that can determine a transmission rate of a data frame to be transmitted to a subordinate wireless terminal from a plurality of transmission rates. In the radio base station apparatus, according to the traffic situation with all the subordinate radio terminals, according to the communication environment between the collective control transmission rate determining means for determining the transmission rate and the radio terminal Selecting either of the transmission rate determining means for determining the transmission rate according to the success or failure of data frame transmission, and determining the transmission rate by the selected means. A radio base station apparatus is provided.

  According to the first aspect of the present invention, the radio base station apparatus performs either one of the collective control transmission rate determination means and the individual control transmission rate determination means according to the success or failure of data frame transmission. In order to select and determine the transmission rate of the data frame by the selected means, the transmission rate depends not only on the communication environment with each of the subordinate radio terminals but also on the traffic situation with all of the subordinate radio terminals. Can be controlled. By controlling the transmission rate as described above, it is possible to reduce the collision probability between the data frames, improve the arrival probability to the data frame transmission destination, and shorten the transmission delay time. As a result, data frames can be transmitted efficiently, and a certain transmission quality can be maintained.

  According to a second aspect of the present invention, in the radio base station apparatus according to the first aspect, the collective control transmission rate determining means is an average of all of the subordinate radio terminals that have successfully transmitted data frames. If it is determined that the transmission quality of the data frame has deteriorated due to an increase in the traffic flow rate, all wireless terminals that have successfully transmitted the data frame among the subordinate wireless terminals The transmission rate of the data frame is increased.

  According to the second aspect of the present invention, the collective control transmission rate determination means increases the average traffic flow of all the subordinate radio terminals even when the transmission of the data frame is successful. If it is determined that the data frame transmission quality has deteriorated, increase the data frame transmission rate of all the wireless terminals that have successfully transmitted the data frame among the subordinate wireless terminals. Therefore, the collision probability between data frames can be lowered. For this reason, the number of retransmissions of the data frame is reduced, the data frame can be transmitted efficiently, and the transmission quality can be kept constant.

According to a third aspect of the present invention, in the radio base station apparatus according to the first or second aspect, the dedicated control transmission rate determining means has failed to transmit a data frame and communicates with the radio terminal. When it is determined that the transmission quality of the data frame is deteriorated due to the deterioration of the environment, the transmission rate of the data frame to the wireless terminal is lowered.
According to the third aspect of the invention, in addition to the collective control of the transmission rate, the probability of arrival of the data frame is increased by lowering the transmission rate to the wireless terminal that failed to transmit the data frame. Therefore, it is possible to efficiently transmit data frames to all of the subordinate wireless terminals, and to maintain a certain transmission quality.

  According to a fourth aspect of the present invention, in the radio base station apparatus according to any one of the first to third aspects, when the data frame addressed to the subordinate radio terminal is successfully transmitted, the radio terminal And a connection terminal management means for managing the transmission rate control method for the wireless terminal as individual control when transmission of a data frame addressed to the subordinate wireless terminal fails. A collective control transmission rate management means for managing the transmission rate determined by the collective control transmission rate determination means; and an individual control transmission rate management for managing the transmission rate determined by the individual control transmission rate determination means. And when the data frame addressed to the subordinate radio terminal is received, to the radio terminal managed by the connection terminal management means When the transmission rate control method is managed as collective control, the data frame is transmitted to the wireless terminal at the transmission rate managed by the collective control transmission rate management means, and managed by the connection terminal management means If the transmission rate control method for the wireless terminal being managed is managed as individual control, data for transmitting a data frame to the wireless terminal at the transmission rate managed by the individual control transmission rate management means A frame transmission means is further provided.

  According to the fourth aspect of the invention, the connection terminal management means determines whether the transmission rate control method for the wireless terminal is batch control or individual control depending on whether or not the transmission of the data frame addressed to the subordinate wireless terminal is successful. When the data frame transmission means receives a data frame to be transmitted to the subordinate radio terminal, the data frame transmission means collectively performs the transmission rate control method for the radio terminal managed by the connection terminal management means. Since the data frame is transmitted to the wireless terminal at the transmission rate managed by the transmission rate management means during control or the transmission rate management means during individual control, the radio base station apparatus performs the transmission rate determination means during individual control or collective control. The data frame can be transmitted at the transmission rate determined by the temporal transmission rate determining means. Thereby, when receiving a data frame addressed to the subordinate radio terminal, the radio base station apparatus uses a transmission rate control method for the radio terminal, a transmission rate determined according to a communication environment and a traffic situation, Since an appropriate transmission rate can be selected and a data frame can be transmitted, the data frame can be transmitted efficiently and the transmission quality can be maintained.

In the invention according to claim 5, the radio base station apparatus selects a transmission rate from a plurality of selectable transmission rates, and transmits a data frame to a subordinate radio terminal according to the selected transmission rate. In the transmission data control method for performing, when the radio base station apparatus receives a data frame addressed to the subordinate radio terminal, the transmission rate control method for the radio terminal A transmission rate control method acquisition step for acquiring either collective control for controlling the transmission rate according to the traffic situation between them or individual control for controlling the transmission rate according to the communication environment with the wireless terminal A transmission rate acquisition step for acquiring a transmission rate corresponding to the transmission rate control method acquired in the transmission rate control method acquisition step, and the transmission rate The transmission rate obtained in yield step, the data frame transmission step of transmitting the data frame to the wireless terminal,
A transmission rate control method determining step for determining a transmission rate control method for the wireless terminal according to whether or not the transmission of the data frame transmitted in the data frame transmitting step is successful; and the transmission rate control method determining step A transmission data control method comprising a transmission rate determination step for determining a transmission rate in accordance with the transmission rate control method determined in step 1 and the transmission state related to data frame transmission.

  According to the transmission data control method of claim 5, when the radio base station apparatus receives a data frame addressed to a subordinate radio terminal, the radio base station apparatus sets a transmission rate according to the transmission rate control method for the radio terminal, The transmission rate is determined according to the traffic situation and communication environment and is selected and managed, and data frames are transmitted at the selected transmission rate. Therefore, not only the communication environment with each subordinate wireless terminal. The transmission rate can be controlled in accordance with the traffic situation with all the subordinate wireless terminals. By controlling the transmission rate, it is possible to reduce the collision probability of the data frame, improve the arrival probability of the data frame, and shorten the arrival delay time. This makes it possible to efficiently transmit data frames and maintain a certain transmission quality.

  According to the present invention, the radio base station apparatus transmits a data frame to the radio terminal according to a communication environment with each of the subordinate radio terminals and a traffic situation with all of the subordinate radio terminals. Since the transmission rate is controlled, it is possible to efficiently transmit data frames by preventing collision between data frames, non-arrival of data frames to the wireless device, transmission delay, and the like. This makes it possible to maintain a certain transmission quality.

Next, the best mode for carrying out the present invention will be described with reference to the drawings. In each drawing referred to in the following description, the same reference numerals are given to the same parts as in the other drawings.
[1. Constitution]
[1.1. overall structure]
FIG. 1 is a block diagram showing a configuration of a wireless communication system 1 according to an embodiment of the present invention. The wireless communication system 1 is a communication network that performs wireless LAN communication. The wireless communication system 1 is a multi-rate communication system capable of selecting and transmitting a data frame transmission rate from a plurality of transmission rates. As shown in the figure, the radio communication system 1 includes a radio base station 10 and radio terminals 20 under the radio base station 10. Here, “the radio terminal 20 is under the control of the radio base station 10” means that “the radio terminal 20 is located in the service area of the radio base station 10 (is present)”. Means.

In the figure, only one radio base station 10 and one radio terminal 20 are shown, but there are actually many. In the following description, when it is necessary to distinguish each of the plurality of wireless terminals 20, numbers 1, 2,... Are added to the end of the code to indicate “wireless terminal 201”, “wireless terminal 202”. It is distinguished by expressing as.
The wireless base station 10 is a device serving as an access point in wireless LAN communication, and relays transmission / reception of data frames between the wireless terminal 20 under its control and other devices.

The wireless terminal 20 is a personal computer equipped with a wireless LAN card. The wireless LAN card stores a MAC (Media Access Control) address for identifying the wireless terminal 20 when performing wireless LAN communication. In the header of the data frame transmitted and received by the wireless terminal 20, a MAC address is described as transmission destination terminal information or transmission source terminal information.
The wireless terminal 20 may be a communication terminal capable of wireless LAN communication other than a personal computer, and may be, for example, a PDA (Personal Digital Assistance) or a mobile phone.

[1.2. Radio base station]
Next, the configuration of the radio base station 10 will be described. The radio base station 10 has a general computer hardware configuration. Specifically, the radio base station 10 temporarily stores a CPU (Central Processing Unit) that controls the radio base station 10 as a whole, a ROM (Read Only Memory) that stores programs executed at the time of startup, and data. A storage unit including a random access memory (RAM) and a communication interface for controlling the wireless terminal 20 and wireless LAN communication.
Various data and programs are stored in the storage unit of the radio base station 10.
For example, the storage unit of the wireless base station 10 stores a connection terminal management list L1 for storing terminal management information of the wireless terminal 20 to which communication is connected. FIG. 2 shows the data structure of the connected terminal management list L1.

  As shown in the figure, the connected terminal management list L1 is a “connected wireless terminal” that indicates the name of the connected wireless terminal 20 among the wireless terminals 20 under the wireless base station 10, and the communication address of the wireless terminal 20. A certain “MAC address”, “total number of transmitted data frames” representing the total number of data frames transmitted to the wireless terminal 20, “average packet size” representing the data size of the transmitted data frames, received from the wireless terminal 20 "Reception level" representing the radio field intensity of the data frame to be transmitted, "Usable transmission rate" representing the transmission rate usable when transmitting the data frame to the wireless terminal 20, and a transmission rate control method for the wireless terminal 20 However, the “collective control” in which the transmission rate is controlled according to the traffic situation with all the subordinate radio terminals 20 or Configured to include a data indicative of "transmission rate control method" indicating whether "individual control" transmission rate is determined according to the communication environment.

  In the connected terminal management list L1, terminal management information for the wireless terminals 20 that are connected to the wireless base station 10 among the wireless terminals 20 under the wireless base station 10 is registered. Among the terminal management information, “total number of transmission data / frames”, “average packet size”, and “reception level” are updated with a statistical value of a transmission state every predetermined time.

  In addition, the storage unit of the radio base station 10 stores a transmission rate management table L2 used when collectively controlling the transmission rate of data frames. FIG. 3 shows the data structure of the transmission rate management table L2. As shown in the figure, the transmission rate management table L2 includes “the number of radio terminals under the radio base station” indicating the number of radio terminals 20 connected among the radio terminals 20 under the radio base station 10; "Number of collective control terminals" representing the number of radio terminals 20 subject to batch control among the subordinate radio terminals 20 being represented, and representing the number of radio terminals 20 subject to individual control among the connected radio terminals 20 “Number of individual control terminals”, “average traffic flow rate Sa of all terminals” that is an average of traffic flow rates with the connected radio terminals 20, and an average delay time of data frames transmitted to the radio terminals 20 “Average data frame transmission delay time Ta”, which is controlled by the transmission state and used when transmitting data frames to the wireless terminal 20, “transmission transmission rate Da”, transmission rate used in normal time Including “data transmission rate Da2” that is determined in advance and “usable transmission rate Da3” that is a transmission rate that can be used when transmitting a data frame to the wireless terminal 20. The

Among these data items of the transmission rate management table L2, predetermined values are stored in “normal transmission rate Da2” and “usable transmission rate Da3”. Other data items are updated with transmission state statistics at predetermined time intervals.
The storage unit of the radio base station 10 stores a transmission rate management table L3 used when individually controlling the transmission rate of data frames. FIG. 4 shows the data structure of the transmission rate management table L3. As shown in the figure, the transmission rate management table L3 is controlled by the “connected wireless terminal” indicating the name of the connected wireless terminal 20 among the wireless terminals 20 under the wireless base station 10 and the transmission state. "Used data frame transmission rate Db" used when transmitting a data frame to the wireless terminal 20, "Normal data frame transmission rate Db2", which is predetermined as a normal transmission rate, It consists of data representing possible data frame transmission rate Db3 "," data frame transmission delay time T3 ", and" reception level Lv3 ".

Among these data items of the transmission rate management table L3, “normal data frame transmission rate Db2” and “usable data frame transmission rate Db3” store predetermined values. Other data items are updated with transmission state statistics at predetermined time intervals.
Various programs are stored in the storage unit of the radio base station 10. The functions shown in FIG. 5 are realized in the radio base station 10 by the functions realized by the CPU of the radio base station 10 executing these programs and the hardware functions of the radio base station 10 described above. . Each function provided in the radio base station 10 will be described with reference to a functional block diagram of the radio base station 10 shown in FIG.

The data frame receiving unit 11 receives a data frame addressed to the subordinate radio terminal 20. Further, the data frame receiving unit 11 acquires a destination MAC address that is transmission destination terminal information from the header of the received data frame, and notifies the connection terminal management unit 12 of the destination MAC address.
The connected terminal management unit 12 manages the wireless terminals 20 that are connected to the wireless base station 10 among the subordinate wireless terminals 20. Specifically, the connection terminal management unit 12 adds terminal management information related to the wireless terminal 20 to the connection terminal management list L1 when communication for transmitting / receiving data frames to / from the subordinate wireless terminal 20 is connected. to add.

  Further, the connection terminal management unit 12 manages a transmission rate control method for the connected wireless terminals 20 under its control. Specifically, the connection terminal management unit 12 determines that the “transmission rate” of the wireless terminal 20 in the connection terminal management list L1 when the transmission of data frames addressed to the wireless terminal 20 succeeds a predetermined number of times in succession. Change "Control method" to "Batch control". Further, the connection terminal management unit 12, when the transmission of the data frame addressed to the wireless terminal 20 continuously fails for a predetermined number of times, the “transmission rate control method” of the wireless terminal 20 in the connection terminal management list L 1. "To" Individual control ". In addition, in response to the notification request when controlling the transmission rate, the connected terminal management unit 12 changes the “transmission rate control method” of the wireless terminal 20 stored in the connected terminal management list L1 to the transmission rate control unit. 13 is notified.

  Here, as described above, the case where the transmission of the data frame addressed to the wireless terminal 20 is successful means that the ACK frame for the transmitted data frame is normally received from the wireless terminal 20, and the wireless terminal The case where the transmission of the data frame addressed to 20 has failed means that the ACK frame corresponding to the transmitted data frame has not been received from the wireless terminal 20.

  Further, the connection terminal management unit 12 collates the data frame destination MAC address received from the data frame reception unit 11 with the MAC address in the connection terminal management list L1, and there is a match. In this case, terminal management information including a matching MAC address is acquired from the connected terminal management list L1. The connected terminal management unit 12 notifies the transmission rate control unit 13 of the “transmission rate control method” included in the acquired terminal management information.

  The transmission rate control unit 13 controls the transmission rate of the data frame transmitted to the subordinate radio terminal 20. Specifically, the transmission rate control unit 13 receives the notification from the connection terminal management unit 12, and when the “transmission rate control method” of the wireless terminal 20 represents “collective control”, the transmission rate control unit 13 The “transmission transmission rate Da” is acquired from the transmission rate management table L2, and the wireless data frame transmission unit 15 is instructed to transmit the data frame at the transmission rate represented by the “transmission transmission rate Da”. On the other hand, when the “transmission rate control method” of the wireless terminal 20 that has received the notification from the connection terminal management unit 12 represents “individual control”, the transmission rate control unit 13 manages the transmission rate during individual control. Obtains “used data / frame transmission rate Db” from the table L3 and instructs the wireless data / frame transmitting unit 15 to transmit the data frame at the transmission rate represented by the “used data / frame transmission rate Db”. To do.

  Further, the transmission rate control unit 13 includes a transmission state management unit 131, a collective control transmission rate management unit 132, an individual control transmission rate management unit 133, and a transmission rate determination unit 134. The transmission state management means 131 manages the transmission state of the data frame. More specifically, the transmission state management means 131 uses the data frame reception unit 11 and the wireless data frame transmission unit 15 to transmit the number of transmission data frames to the wireless terminal 20, the transmission packet size, the reception level, and the data frame. Information regarding the transmission state such as transmission delay time, traffic flow rate, data frame transmission delay time, etc. is sequentially collected, and an average value of the entire wireless terminal 20 is calculated to create a statistical value of the transmission state. The transmission state management unit 131 notifies the connection terminal management unit 12, the collective control transmission rate management unit 132, and the individual control transmission rate management unit 133 of the transmission state statistical value at predetermined time intervals.

  Further, the transmission state management unit 131 checks whether or not the ACK frame for the transmission data frame has been correctly received by monitoring the ACK frame received by the data frame receiving unit 11. The transmission state management means 131 “transmission rate control method” of the data frame transmission destination radio terminal 20 managed when the data frame has been successfully transmitted a predetermined number of times in succession and managed in the connection terminal management list L1. Is “individual control”, the connection terminal management unit 12 is instructed to change the transmission rate control method for the wireless terminal 20 to batch control. On the other hand, the transmission state management unit 131 continuously transmits the “transmission rate” of the data frame transmission destination radio terminal 20 managed in the connection terminal management list L1 when transmission of the data frame has failed a predetermined number of times. When the “control method” is “collective control”, the connection terminal management unit 12 is instructed to change the transmission rate control method for the wireless terminal 20 to individual control.

  The batch control transmission rate management means 132 manages a transmission rate management table L2 used during batch control. Specifically, the collective control transmission rate management unit 132 updates the transmission rate management table L2 with the statistical value of the transmission state notified from the transmission state management unit 131. The batch control transmission rate management means 132 updates the “transmission transmission rate Da” in the transmission rate management table L2 with the transmission rate determined by the batch control transmission rate determination function 1341. Also, the collective control transmission rate management means 132 notifies the “transmission transmission rate Da” stored in the transmission rate management table L2 in response to the notification request from the transmission rate control unit 13.

  The individual control transmission rate management means 133 manages the transmission rate management table L3 used during individual control. Specifically, the individual control transmission rate management unit 133 updates the transmission rate management table L3 with the transmission state statistics notified from the transmission state management unit 131. The individual control transmission rate management means 133 updates the “used data / frame transmission rate Db” in the transmission rate management table L3 with the transmission rate determined by the individual control transmission rate determination function 1342. Further, the individual control transmission rate management means 133 responds to the notification request from the transmission rate control unit 13 and stores the “use data / frame transmission rate of the corresponding wireless terminal 20 stored in the transmission rate management table L3. Db ".

The transmission rate determining unit 134 determines the transmission rate of the data frame to be transmitted to the wireless terminal 20. The transmission rate determining means 134 includes a collective control transmission rate determining function 1341 and an individual control transmission rate determining function 1342.
The transmission rate determination function 1341 at the time of collective control allows data frames to be transmitted when the transmission of data frames to the subordinate radio terminals 20 succeeds a predetermined number of times and the average traffic flow of all the subordinate radio terminals 20 increases. When it is determined that the transmission quality of the frame is deteriorated, the transmission rate of the data frame is increased to all the wireless terminals 20 that have successfully transmitted the data frame among the subordinate wireless terminals 20 . Here, the transmission rate determination function 1341 at the time of the collective control is a fixed reference value in which the “all terminal average traffic flow rate Sa” and the “average data / frame transmission delay time Ta” in the transmission rate management table L2 are predetermined. In the following cases, it is determined that the transmission quality of the data frame has deteriorated due to an increase in the average traffic flow rate of all the subordinate radio terminals 20.

  The transmission rate determination function 1342 for individual control is such that the transmission of data frames addressed to the wireless terminal 20 continuously fails a predetermined number of times, and the communication environment with the wireless terminal 20 deteriorates, so that the transmission quality of the data frame When it is determined that the data frame has deteriorated, the data frame transmission rate to the wireless terminal 20 is lowered. The individual control transmission rate determination function 1342 is such that the “data frame transmission delay time T3” in the transmission rate management table L3 is equal to or greater than a predetermined reference value, and the “reception level Lv3” is predetermined. When the reference value is equal to or lower than the reference value, it is determined that the transmission quality of the data frame is deteriorated due to the deterioration of the communication environment with the wireless terminal 20.

The access control unit 14 performs access control according to a method such as DCF using CSMA / CA defined in IEEE802.11. That is, the access control unit 14 carrier senses the DIFS and Backoff time prior to data frame transmission, and if the channel of the radio base station 10 is in an idle state, the access control unit 14 transmits data to the radio base station 10.・ Access control such as allowing frame transmission.
The wireless data frame transmission unit 15 transmits the data frame received by the data frame reception unit 11. At this time, the wireless data frame transmission unit 15 transmits a data frame according to the access control performed by the access control unit 14.

  The wireless data frame transmission unit 15 transmits a data frame according to the transmission rate managed by the collective control transmission rate management unit 132 and the individual control transmission rate management unit 133. Specifically, when the data frame receiving unit 11 receives a data frame addressed to the wireless terminal 20, the wireless data frame transmitting unit 15 stores the “of the wireless terminal 20 stored in the connected terminal management list L 1. When the “transmission rate control method” indicates “batch control”, the transmission rate control unit 13 receives a notification of “transmission transmission rate Da” at the time of batch control, and transmits a data frame at the notified transmission rate. Send. On the other hand, when the “transmission rate control method” of the wireless terminal 20 stored in the connected terminal management list L1 represents “individual control”, the wireless data / frame transmission unit 15 transmits the transmission rate control unit 13. Receives a notification of “used data frame transmission rate Db” of individual control, and transmits a data frame at the transmission rate at which the notification is received.

[2. Operation]
Next, the operation in the above configuration will be described with reference to FIG. 6, FIG. 7, and FIG.
As a premise, in the following description, when the radio base station 10 refers to the connection terminal management list L1, the transmission rate management table L2, and the transmission rate management table L3 stored in the storage unit, FIG. Assume that data having the contents shown in FIG. 4 is stored.

[2.1. Transmission data control procedure]
A data control procedure when the radio base station 10 receives a data frame addressed to the subordinate radio terminal 20 will be described with reference to FIG.
First, when the data frame receiving unit 11 of the radio base station 10 receives a data frame (step S001; Yes), a destination MAC address that is destination terminal information is obtained from the header of the received data frame. Is acquired (step S002), and the connection terminal management unit 12 is notified.

  The connection terminal management unit 12 determines whether the destination terminal information of the data frame exists in the connection terminal management list L1 (step S003). Specifically, the connection terminal management unit 12 searches the connection terminal management list L1 in the storage unit, and the MAC address that matches the destination MAC address received from the data frame reception unit 11 is in the connection terminal management list L1. Determine if it exists. If it exists in the connected terminal management list L1 (step S003; Yes), the connected terminal management unit 12 acquires terminal management information including a matching MAC address from the connected terminal management list L1 (step S004). . The connected terminal management unit 12 notifies the transmission rate control unit 13 of the “transmission rate control method” included in the acquired terminal management information.

  The transmission rate control unit 13 refers to whether the received “transmission rate control method” represents “collective control” or “individual control”. When the “transmission rate control method” represents “collective control” (step S005; Yes), the transmission rate control unit 13 sends the transmission control during the collective control to the transmission rate management means 132 during the collective control. Request rate notification. The collective control transmission rate management means 132 acquires “transmission transmission rate Da” (in this case, “2 Mbit / s”) from the collective control transmission rate management table L2, and notifies the transmission rate control unit 13 of it. The transmission rate control unit 13 notifies the wireless data / frame transmission unit 15 of the received “transmission transmission rate Da”. On the other hand, when the “transmission rate control method” represents “individual control” (step S005; No), the transmission state management unit 131 instructs the transmission rate management unit 133 at the time of individual control. Request notification of transmission transmission rate. The individual control transmission rate management means 133 acquires the “used data / frame transmission rate Db” (in this case, “2 Mbit / s”) from the transmission rate management table L3 at the time of individual control (step S008). Notify the control unit 13. The transmission rate control unit 13 notifies the wireless data / frame transmission unit 15 of the received “used data / frame transmission rate Db”.

The access control unit 14 performs data frame access control. The wireless data frame transmission unit 15 transmits a data frame to the wireless terminal 20 according to the access control by the access control unit 14 and according to the transmission rate notified from the transmission rate control unit 13 (step S009).
If the destination MAC address included in the header of the data frame is not in the connected terminal management list L1 (step S003; No), the transmission rate control unit 13 instructs the transmission rate management unit 132 for collective control. Request notification of current transmission transmission rate. The collective control transmission rate management means 132 notifies the transmission rate control unit 13 of “transmission transmission rate Da” (here, “2 Mbit / s”) in the transmission rate management table L2. The transmission rate control unit 13 notifies this “transmission transmission rate Da” to the wireless data / frame transmission unit 15. The wireless data frame transmission unit 15 transmits the data frame at the transmission rate at the time of collective control represented by “transmission transmission rate Da” (step S010). Thereafter, the connected terminal management unit 12 adds terminal management information related to the data / frame transmission destination wireless terminal 20 to the connected terminal management list L1 (step S011).

  After transmitting the data frame addressed to the wireless terminal 20, the process proceeds to step S012, and the transmission state management means 131 monitors the ACK frame received by the data frame receiving unit 11 to thereby acknowledge the transmitted data frame. Check whether the frame was received. If the ACK frame has been correctly received (step S012; Yes), the transmission state management unit 131 requests the connection terminal management unit 12 to notify the transmission rate control method for the wireless terminal 20. The connection terminal management unit 12 acquires the “transmission rate control method” of the wireless terminal 20 from the connection terminal management list L1 (step S013), and notifies the transmission state management means 131 of it. In the transmission state management means 131, the acquired “transmission rate control method” of the wireless terminal 20 represents “individual control” (step S014; Yes), and further, the ACK frame is received a predetermined number of times in advance. If successful (step S015; Yes), an instruction to change the transmission rate control method for the radio terminal 20 to batch control is transmitted to the connected terminal management unit 12. The connected terminal management unit 12 changes the “transmission rate control method” of the wireless terminal 20 in the connected terminal management list L1 from “individual control” to “batch control” (step S016).

On the other hand, if the ACK frame for the data frame addressed to the wireless terminal 20 cannot be received correctly (step S012; No), and if the ACK frame reception fails continuously thereafter (step S017; Yes), the transmission state The management unit 131 requests the connection terminal management unit 12 to notify the transmission rate control method for the wireless terminal 20. The connection terminal management unit 12 acquires the “transmission rate control method” of the wireless terminal 20 from the connection terminal management list L1 (step S018), and notifies the transmission state management unit 131 of it. If the acquired “transmission rate control method” of the wireless terminal 20 represents “batch control” (step S019; Yes), the transmission state management unit 131 sets the transmission rate control method for the wireless terminal 20 to individual control. An instruction to change is transmitted to the connection terminal management unit 12. The connected terminal management unit 12 changes the “transmission rate control method” of the wireless terminal 20 in the connected terminal management list L1 from “collective control” to “individual control” (step S020).
Finally, the connection terminal management unit 12 updates the connection terminal management list L1 with the contents changed in the above steps (step S021).

[2.2. Batch control]
Next, a transmission rate control procedure performed when the transmission rate control method for the radio terminal 20 is changed from individual control to batch control will be described with reference to FIG.
When processing is performed according to the procedure shown in FIG. 6 and a wireless terminal 20 is generated whose transmission rate control method has been changed from individual control to collective control (step S101), transmission rate management during collective control of the radio base station 10 is performed. The means 132 updates the “collective control terminal number” (here “6”) and the “individual control terminal number” (here “1”) in the transmission rate management table L2 (step S102). Specifically, the collective control transmission rate management means 132 updates the “collective control terminal number” with a value obtained by adding “1” to the number of terminals represented by the “collective control terminal number”. The number of “individual control terminals” is updated with a value obtained by subtracting “1” from the number of terminals represented by “

  Next, the collective control transmission rate determining function 1341 gives the collective control transmit rate management means 132 the statistical values “average data / frame transmission delay time Ta” and “ A notification of “all terminal average traffic flow rate Sa” is requested. Based on the transmission rate management table L2, the collective control transmission rate management means 132 determines that “average data / frame transmission delay time Ta” (here “0.5 msec”) and “average traffic flow rate Sa for all terminals” (here “1.5 Mbit”). / s ″) (step S103), and notifies the collective control transmission rate determination function 1341. The collective control transmission rate determination function 1341 determines the transmission state from these statistical values (step S104). Specifically, when both “average data / frame transmission delay time Ta” and “all-terminal average traffic flow rate Sa” exceed a predetermined reference value, a transmission rate determination function 1341 at the time of collective control Determines that the transmission quality has deteriorated due to packet collision caused by traffic increase in the radio section between the radio base station 10 and the radio terminal 20 (step S105).

  Then, the batch control transmission rate determination function 1341 requests the batch control transmission rate management means 132 to notify the transmission rate used during batch control and the usable transmission rate. Based on the transmission rate management table L2, the transmission rate management means 132 in the collective control uses “transmission transmission rate Da” (here “2 Mbit / s”) and “usable transmission rate Da3” (here “1, 2, 5.5 Mbit / s”). s ″) and notifies the transmission rate determination function 1341 during collective control. The transmission rate determination function 1341 at the time of collective control uses a transmission rate (in this case, “5.5 Mbit / s”) higher than the currently used “transmission rate Da” among the “usable transmission rates Da3”. To be used (step S106). The batch control transmission rate determination function 1341 notifies the batch control transmission rate management means 132 of the determined transmission rate “5.5 Mbit / s”. The collective control transmission rate management means 132 changes the “transmission transmission rate Da” in the transmission rate management table L2 to the transmission rate “5.5 Mbit / s” (step S107).

  On the other hand, if “average data / frame transmission delay time Ta” and “all-terminal average traffic flow rate Sa” are equal to or less than a predetermined reference value in step S104, the collective control transmission rate determination function 1341 is generated due to traffic increase. It is determined that there is a low possibility of transmission quality degradation due to packet collision (step S108). Then, the collective control transmission rate determination function 1341 requests the collective control transmission rate management means 132 to notify the currently used transmission rate and the normal transmission rate. The collective control transmission rate management means 132 acquires “transmission transmission rate Da” and “normal transmission rate Da2” from the transmission rate management table L2 (step S109), and notifies the collective control transmission rate determination function 1341. To do. The batch control transmission rate determination function 1341 compares the values represented by “transmission transmission rate Da” and “normal transmission rate Da2”, and the current transmission rate “transmission transmission rate Da” is “normal transmission”. If it is higher than the rate Da2 (here, “2 Mbit / s”) (step S110; Yes), the transmission at the time of collective control is performed so that the “transmission transmission rate Da” is changed to the value of the “normal transmission rate Da2”. The rate management means 132 is instructed. The collective control transmission rate management means 132 changes the “transmission transmission rate Da” in the transmission rate management table L2 to the value of the “normal transmission rate Da2” (step S011). Note that the processing from step S108 to step S111 plays a role of returning the transmission rate set high in the processing from step S105 to step S107 to the original transmission rate.

[2.3. Individual control]
Next, a transmission rate control procedure performed when the transmission rate control method for the connected wireless terminal 201 is changed from collective control to individual control will be described with reference to FIG.
When processing is performed in accordance with the procedure shown in FIG. 6 and a wireless terminal 201 whose transmission rate control method is changed from collective control to individual control occurs (step S201), the individual control transmission rate determination function 1342 performs the individual control. It requests the hourly transmission rate management means 133 to notify the data frame transmission delay time and the reception level of the wireless terminal 201. The transmission rate management means 133 for individual control uses the “data frame transmission delay time T3” (in this case “0.5 msec”) and “reception level Lv3” (this) from the transmission rate management table L3 for individual control. In the case of “−60 dBm”) (step S202), and notifies the transmission rate determination function 1342 during individual control. The individual control transmission rate determination function 1342 determines the transmission state with the wireless terminal 201 based on the acquired “data frame transmission delay time T3” and “reception level Lv3” (step S203). Specifically, when “data frame transmission delay time T3” is equal to or greater than a predetermined reference value and “reception level Lv3” is below a predetermined reference value ( In step S203; Yes), the transmission rate determination function 1342 at the time of individual control is caused by the transmission quality deterioration due to the deterioration of the communication environment between the wireless base station 10 and the wireless terminal 201 because the cause of the data frame transmission failure addressed to the wireless terminal 201 is (Step S204). The individual control transmission rate determination function 1342 then requests the individual control transmission rate management means 133 to notify the usable transmission rate. The individual control transmission rate management means 133 acquires “usable data / frame transmission rate Db3” (in this case, “1, 2, 5.5, 11 Mbit / s”) from the transmission rate management table L3 (step S205). The individual control transmission rate determination function 1342 is notified. The individual control transmission rate determination function 1342 receives the currently used “used data frame transmission rate Db” from the “available data frame transmission rate Db3” (here, “2 Mbit / s”). s "), a lower transmission rate (here," 1 Mbit / s ") is determined as the data frame transmission rate and notified to the individual control transmission rate management means 133. The individual control transmission rate management means 133 updates the “used data / frame transmission rate Db” in the transmission rate management table L3 with the received data / frame transmission rate “1 Mbit / s”.

  On the other hand, when “data frame transmission delay time T3” is less than a certain reference value or “reception level Lv3” is more than a certain reference value in step S203 (step S203; No), the transmission rate during individual control The determination function 1342 determines that the cause of the data frame transmission failure addressed to the wireless terminal 201 is that the transmission quality has deteriorated due to the increase in traffic in the wireless section (step S207), and transmission at the time of individual control Requests the rate management means 133 to change the currently used transmission rate to the normal transmission rate. The individual control transmission rate management means 133 acquires “normal data frame transmission rate Db2” (in this case, “2 Mbit / s”) recorded in the transmission rate management table L3 (step S208). The individual control transmission rate management means 133 updates the “used data / frame transmission rate Db” in the transmission rate management table L3 with the acquired “normal data / frame transmission rate Db2” value “2 Mbit / s”. (Step S209). Note that the processing from step S207 to step S209 plays a role of returning the transmission rate set low in the processing from step S204 to step S206 to the original transmission rate.

  As described above, the radio base station 10 has two means as means for controlling the data frame transmission rate. That is, the radio base station 10 determines the transmission rate from the statistical value of the transmission state with all the connected radio terminals 20 and is the same for all the radio terminals 20 that have been successfully transmitted. There are means for designating a transmission rate and means for individually controlling the transmission rate between the radio base station 10 and each radio terminal 20 according to the communication environment of each radio terminal 20, and the two means are used in combination. To control the transmission rate.

  For this reason, when the transmission of the data frame transmitted to the wireless terminal 20 fails, not only the arrival probability of the transmission data frame can be increased by changing the transmission rate addressed to the wireless terminal 20, but also the transmission is successful. In this case, the data transmission status of all the radio terminals 20 under the radio base station 10 can be grasped, and it can be determined that the transmission status has deteriorated due to an increase in traffic due to the transmission of data frames of other radio terminals 20. In this case, it is possible to control the transmission rate of all the subordinate radio terminals 20. This makes it possible to efficiently transmit data frames to the subordinate radio terminal 20 and maintain a certain transmission quality.

[3. Modified example]
Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and various modifications can be made within the scope of the technical idea. As modifications, for example, the following can be considered.
(1) Although communication of the wireless communication system 1 in the above-described embodiment has been described as wireless LAN communication, it may be wireless communication and is not limited to the wireless LAN. For example, the radio terminal 20 may be a mobile communication terminal, and the radio base station 10 and the radio terminal 20 may transmit and receive data via a mobile packet communication network.

(2) The transmission data control and transmission rate control procedures shown in FIGS. 6, 7, and 8 are merely examples. Collective control transmission rate determination means for determining the transmission rate according to the traffic situation with all of the subordinate wireless terminals 20 and an individual for determining the transmission rate according to the communication environment with each wireless terminal 20 The above-described embodiment is any procedure as long as it is a procedure for selecting any one of the control transmission rate determining means according to the success or failure of data frame transmission and controlling the data frame transmission rate by the selected means. It is not limited to.

  For example, in the above-described embodiment, the transmission rate control method is changed when the ACK frame is continuously received a predetermined number of times or when the reception of the ACK frame is continuously failed a predetermined number of times. The transmission rate control method may be changed when an ACK frame is received for one transmission data frame, or the transmission rate control method may be changed according to the probability of receiving an ACK frame. Good.

  In the above-described embodiment, the data frame transmission delay time, the average traffic flow rate, and the reception level are used as the index for determining the transmission status such as the traffic status and the communication environment. Is not limited to this, and an optimal index can be selected according to the theory or empirical rule. In addition, the transmission state is determined based on whether these indices are higher or lower than a predetermined constant reference value. However, the determination condition is not limited to this, and the predetermined reference value may include a transmission state. The most suitable reference value can be selected to improve efficiency.

(3) The data configurations of the connection terminal management list L1, the transmission rate management table L2, and the transmission rate management table L3 in the embodiment described above are examples. For example, in the connection terminal management list L1, only the “transmission rate control method” of each wireless terminal 20 may be managed, and various statistical values may be managed by the transmission rate management table L3. The list L1 and the transmission rate management table L3 may be integrated into one list. Further, when the subordinate wireless terminal 20 is disconnected, it may be deleted from the connected terminal management list L1.

It is a block diagram which shows the whole structure of the radio | wireless communications system which concerns on embodiment of this invention. It is a figure which shows the data structure of the connection terminal management list | wrist which concerns on the embodiment. It is a figure which shows the data structure of the transmission rate management table | surface used when carrying out batch control of the transmission rate of the data frame which concerns on the embodiment. It is a figure which shows the data structure of the transmission rate management table | surface used when carrying out the individual control of the transmission rate of the data frame which concerns on the embodiment. It is a functional block diagram of the radio base station according to the embodiment. 5 is a flowchart showing a data control procedure when the radio base station according to the embodiment receives a data frame. It is a flowchart which shows the transmission rate control procedure in case the transmission rate control method which concerns on the embodiment is batch control. It is a flowchart which shows the transmission rate control procedure in case the transmission rate control method which concerns on the embodiment is individual control. It is a figure which shows the procedure of the radio | wireless access control by DCF in the IEEE802.11 system of a prior art. It is a figure which shows the transmission procedure by the multirate control of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless communication system 10 Wireless base station 11 Data frame receiving part 12 Connection terminal management part 13 Transmission rate control part 14 Access control part 15 Wireless data frame transmission part 20, 201 Wireless terminal 131 Transmission state management means 132 Transmission in collective control Rate management means 133 Transmission rate management means 134 for individual control Transmission rate determination means 1341 Transmission rate determination function for collective control 1342 Transmission rate determination function for individual control Da Transmission transmission rate Da2 Normal transmission rate Da3 Usable transmission rate Db Data used Frame transmission rate Db2 Normal data frame transmission rate Db3 Data frame transmission rate L1 Connection terminal management list L2 Transmission rate management table L3 Transmission rate management table Lv3 Reception level Sa Average traffic flow T3 for all terminals Data frame transmission Extension time Ta average data frame transmission delay time

Claims (5)

In a multi-rate compatible radio base station apparatus capable of determining a transmission rate of a data frame transmitted to a subordinate radio terminal from a plurality of transmission rates,
A collective control transmission rate determining means for determining the transmission rate according to a traffic situation with all of the subordinate wireless terminals;
Depending on the communication environment with the wireless terminal, one of the transmission rate determining means for determining the transmission rate is selected according to the success or failure of data frame transmission, and the selected A wireless base station apparatus, wherein the transmission rate is determined by means. The batch control transmission rate determination means includes:
If transmission of the data frame is successful and it is determined that the transmission quality of the data frame has deteriorated due to an increase in the average traffic flow rate of all of the subordinate radio terminals, the subordinate radio 2. The radio base station apparatus according to claim 1, wherein a transmission rate of the data frame to all radio terminals that have successfully transmitted the data frame among the terminals is increased. The individual control transmission rate determination means includes:
If it is determined that the transmission quality of the data frame is deteriorated due to the failure of the transmission of the data frame and the deterioration of the communication environment with the wireless terminal, the data to the wireless terminal The radio base station apparatus according to claim 1 or 2, wherein a frame transmission rate is lowered. When the transmission of the data frame addressed to the subordinate radio terminal succeeds, the transmission rate control method for the radio terminal is managed as a collective control,
When transmission of a data frame addressed to the subordinate radio terminal fails, connection terminal management means for managing a transmission rate control method for the radio terminal as individual control;
Collective control transmission rate management means for managing the transmission rate determined by the collective control transmission rate determination means;
Individual control transmission rate management means for managing the transmission rate determined by the individual control transmission rate determination means;
When a data frame addressed to the subordinate wireless terminal is received,
When the transmission rate control method for the wireless terminal managed by the connection terminal managing means is managed as a batch control, the wireless terminal is controlled by the transmission rate managed by the batch control transmission rate managing means. Send data frames,
When the transmission rate control method for the wireless terminal managed by the connection terminal managing means is managed as individual control, the wireless terminal is controlled by the transmission rate managed by the individual control transmission rate managing means. The radio base station apparatus according to any one of claims 1 to 3, further comprising: a data frame transmission unit that transmits a data frame. In a transmission data control method in which a radio base station device selects a transmission rate from a plurality of selectable transmission rates and transmits a data frame to a subordinate radio terminal according to the selected transmission rate.
When the radio base station apparatus receives a data frame addressed to the subordinate radio terminal, a transmission rate control method for the radio terminal is transmitted according to traffic conditions with all the subordinate radio terminals. A transmission rate control method acquisition step of acquiring which is one of collective control for controlling a rate and individual control for controlling a transmission rate according to a communication environment with the wireless terminal;
A transmission rate acquisition step of acquiring a transmission rate corresponding to the transmission rate control method acquired in the transmission rate control method acquisition step;
A data frame transmission step for transmitting a data frame to the wireless terminal according to the transmission rate acquired in the transmission rate acquisition step;
A transmission rate control method determination step for determining a transmission rate control method for the wireless terminal according to whether or not the transmission of the data frame transmitted in the data frame transmission step is successful;
A transmission data control method comprising: a transmission rate determination method for determining a transmission rate according to the transmission rate control method determined in the transmission rate control method determination step and a transmission state related to transmission of a data frame.

Images