JP2004320618A - Radio access system and radio access method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assure service quality to each radio terminal by correcting imbalance of transmission data amount between radio terminals in the same system. <P>SOLUTION: In a radio access system equipped with a plurality of radio data transmitters which transmit the data via a radio line and a radio data receiver which receive the data transmitted from a group of radio data transmitters, the radio data receiver monitors the transmission data amount by every radio data transmitter and when a radio data transmitter which transmits the transmission data quantity exceeding a threshold is detected, informs the fact. The radio data transmitters control transmission traffic by receiving this information. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technology for controlling a wireless band used for communication connected via a wireless line between a wireless data receiving device and a plurality of wireless data transmitting devices.
[0002]
[Prior art]
The access method of the wireless access system used as the access system of the wired network is based on a centralized control method in which the wireless base station manages the transmission timing of all wireless terminals, and an independent wireless system including the base station and each wireless terminal. There is a distributed control method in which transmission timing is determined and transmission is performed.
[0003]
In the distributed control method, there is no difference in the transmission method between the wireless base station and the wireless terminal, and the base station configuration is simpler than the centralized control method. Further, since there is no need to control the wireless terminal from the base station, a control signal is not required, and high throughput can be realized.
[0004]
In the distributed control method, a distributed control algorithm such as CSMA (Carrier Scan Multiple Access) is used for an access method in a wireless section. In these methods, data transmission in each wireless device of a wireless base station and a wireless terminal station is performed by each Since the wireless terminal independently determines the data transmission timing, the amount of wireless band used by the wireless device differs for each terminal.
[0005]
For example, a terminal that generates a large amount of data from a wireless terminal uses a large amount of the wireless band, and a terminal that generates a small amount of data uses a small amount of the wireless band. That is, the usage of the wireless band is determined on a first-come, first-served basis (for example, see Non-Patent Document 1).
[0006]
[Non-patent document 1]
IEEE std 802.11-Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications
[0007]
[Problems to be solved by the invention]
In such a wireless access system, when a certain wireless terminal generates an extremely large amount of traffic, the wireless terminal uses a large number of wireless bands, and the wireless terminals in the same system do not use a large amount of wireless band. There is a problem that the balance is generated, and the other wireless terminals reduce the amount of used wireless bandwidth and decrease the throughput. In addition, considering a service for guaranteeing a band for a specific wireless terminal, there is also a problem that the service cannot be implemented because there is no band control means. As described above, in the wireless access system using the distributed control method, an imbalance in the used wireless band may occur between wireless terminals.
[0008]
The present invention has been made in such a background, and an object of the present invention is to provide a radio access system and a method capable of correcting such imbalance and guaranteeing service quality for each radio terminal. And
[0009]
[Means for Solving the Problems]
A first aspect of the present invention is a wireless access system including a plurality of wireless data transmitting devices that transmit data via a wireless line, and a wireless data receiving device that receives data transmitted from a wireless data transmitting device group It is.
[0010]
Here, it is a feature of the present invention that the wireless data receiving device monitors a transmission data amount for each of the wireless data transmitting devices, and the monitoring unit transmits the transmission data amount exceeding a threshold value. Means for transmitting congestion information notifying the fact when the wireless data transmitting device is detected to the wireless data transmitting device, wherein the wireless data transmitting device receives the congestion information and reduces the amount of transmitted data. There is a means for adjusting (claim 1). As a result, it is possible to correct the imbalance in the used wireless bandwidth between the wireless terminals in the same system.
[0011]
The transmitting means may include means for mounting the congestion information in a part of a reception confirmation signal used for data reception confirmation (claim 2). Accordingly, there is no need to provide a separate signaling procedure for transmitting and receiving the congestion information, and the conventional signaling procedure can be used as it is.
[0012]
The means for adjusting the amount of transmission data may include means for increasing or decreasing the amount of transmission data according to the content frequency of the congestion information during a predetermined number of receptions of the reception confirmation signal (claim 3). As a result, the amount of transmission data can be finely adjusted, so that the necessary minimum amount of transmission data can be limited.
[0013]
For example, the means for increasing / decreasing the transmission data amount includes means for extending a transmission interval by a predetermined time each time the reception confirmation signal includes the congestion information, and means for receiving the reception confirmation received after the transmission interval is extended. Means for restoring the transmission interval when the signal does not include the congestion information (claim 4). The recovery unit may include a unit that recovers a transmission interval by a predetermined time every time the reception confirmation signal that does not include the congestion information is received (claim 5).
[0014]
That is, if the extended transmission interval is set to t for one reception of the congestion information, and if the congestion information is continuously received n times, the extension of nxt time is performed. It is. Further, after the congestion information is received a plurality of times and the transmission interval is extended, if the congestion information is not received, the extended transmission interval may be returned by, for example, t time. . In this case, if an acknowledgment signal that does not include the congestion information is received n times or more consecutively after the transmission interval is extended for nxt time, the transmission interval becomes the time before the transmission interval is shortened. To recover. Alternatively, after the congestion information is received a plurality of times and the transmission interval is extended, if the congestion information is not received, the extended transmission interval may be restored at once.
[0015]
A means for calculating a ratio of the wireless data transmitting devices transmitting a data amount exceeding a threshold for all the wireless data transmitting devices in the same system; and a means for changing a threshold according to the ratio. (Claim 6). According to this, it is possible to perform appropriate control based on the current state of the congestion state in the system, as compared with a case where the threshold is uniformly determined. For example, assuming that the transmission data amount of a large number of wireless data transmission devices exceeds the threshold value, it is refrained from setting the current threshold value larger than this, and it is determined that it is better to change the current threshold value to a smaller value. If only a small number of wireless data transmitting apparatuses have a transmission data amount exceeding the threshold value, it is determined that there is no problem even if the current threshold value is set larger than this.
[0016]
A second aspect of the present invention is a wireless access system including a plurality of wireless data transmitting apparatuses for transmitting data via a wireless line, and a wireless data receiving apparatus for receiving data transmitted from a wireless data transmitting apparatus group The wireless data receiving device is applied to a wireless data receiving device.
[0017]
Here, a feature of the present invention is that a means for monitoring the amount of transmission data for each of the wireless data transmission devices, and that the monitoring means detects the wireless data transmission device for transmitting the amount of transmission data exceeding a threshold value Means for transmitting congestion information notifying the fact to the wireless data transmitting apparatus.
[0018]
The transmitting means may include means for mounting the congestion information in a part of a reception confirmation signal used for data reception confirmation (claim 8).
[0019]
Further, a means for calculating a ratio of the wireless data transmitting devices transmitting a data amount exceeding a threshold for all the wireless data transmitting devices in the same system is provided, and a unit for changing the threshold according to the ratio is provided. It can be provided (claim 9).
[0020]
A third aspect of the present invention is a wireless access system including a plurality of wireless data transmitting apparatuses for transmitting data via wireless lines and a wireless data receiving apparatus for receiving data transmitted from a group of wireless data transmitting apparatuses. The wireless data transmitting device applied to the present invention.
[0021]
Here, the feature of the present invention is that the wireless data receiving apparatus receives congestion information for notifying the wireless data transmitting apparatus that transmits a transmission data amount exceeding a threshold from the wireless data receiving apparatus and reduces the transmission data amount. There is provided an adjusting means (claim 10).
[0022]
The means for adjusting the amount of transmission data may include means for increasing or decreasing the amount of transmission data in accordance with the frequency of the congestion information contained in the predetermined number of receptions of the acknowledgment signal (claim 11). The means for increasing / decreasing the transmission data amount includes means for extending a transmission interval by a predetermined time each time the congestion information is included in the reception confirmation signal, and means for extending the transmission confirmation time after the transmission interval is extended. Means for restoring the transmission interval when the congestion information is not included (claim 12). The recovering unit may include a unit that recovers a transmission interval by a predetermined time every time the reception confirmation signal not including the congestion information is received (claim 13).
[0023]
A fourth aspect of the present invention is a wireless access method in which one wireless data receiving device receives wireless data transmitted from a plurality of wireless data transmitting devices via wireless lines.
[0024]
Here, a feature of the present invention is that the wireless data receiving device monitors the amount of transmission data for each of the wireless data transmitting devices, and detects the wireless data transmitting device that transmits the amount of transmission data exceeding a threshold value. When this is done, congestion information notifying the fact is transmitted to the wireless data transmitting apparatus, and the wireless data transmitting apparatus receives the congestion information and adjusts the amount of transmitted data (claim 14).
[0025]
The wireless data receiving apparatus may include the congestion information in a part of a reception confirmation signal used for data reception confirmation (claim 15).
[0026]
The wireless data transmitting apparatus can increase or decrease the amount of transmission data according to the frequency of the congestion information included in the predetermined number of receptions of the reception confirmation signal (claim 16).
[0027]
The wireless data device, the reception confirmation signal extends the transmission interval by a predetermined time each time the congestion information is included, the reception confirmation signal received after the transmission interval is extended includes the congestion information If not, the transmission interval can be restored (claim 17). Each time the reception confirmation signal not including the congestion information is received, the transmission interval may be restored by a predetermined time (claim 18).
[0028]
The ratio of the wireless data transmitting devices transmitting the data amount exceeding the threshold for all the wireless data transmitting devices in the same system is calculated, and the threshold can be changed according to the ratio (claim 19). ).
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a wireless access system according to an embodiment of the present invention. The wireless access system in the figure includes one wireless terminal B connected to a wired network, and a plurality of wireless terminals # 1 to # 3 connected to the wired network via the wired wireless terminal B. You. An access method (for example, CSMA) using a distributed control algorithm is used for communication between wireless terminals via wireless.
[0030]
FIG. 2 shows a functional configuration on the transmitting side of the wireless terminal, and FIG. 3 shows a functional configuration on the receiving side of the wireless terminal. In a normal wireless terminal, one terminal has both functions of a transmitting side and a receiving side.
[0031]
As shown in FIG. 2, the transmitting side includes a data transmitting unit 11 for transmitting data to a communication partner, a receiving unit 14 for receiving a confirmation signal from the other party for notifying the success of data reception, It comprises a congestion information detection unit 13 for detecting the included congestion information and a traffic control unit 12 for controlling the data transmission timing and adjusting the amount of transmission data of the terminal (claims 1 and 10).
[0032]
When there is data to be transmitted to the wireless terminal, the data transmission unit 11 transmits the data at the transmission timing instructed by the traffic control unit 12. After data transmission, the wireless terminal waits for a reception acknowledgment signal from the communication partner, and if it can receive it, the transmission procedure is completed. On the transmission side, when receiving the reception confirmation signal, the congestion information included in the reception confirmation signal is detected by the congestion information detection unit 13 and the information is notified to the traffic control unit 12. According to the congestion information, the traffic control unit 12 adjusts the transmission traffic by increasing the transmission interval of the transmission data in the case of congestion and shortening the transmission interval of the transmission data in the case of no congestion. 4, 5, 11, 12).
[0033]
As shown in FIG. 3, the receiving side includes a data receiving unit 15 for receiving data transmitted from the communication partner, and a confirmation signal transmitting unit for transmitting a reception confirmation signal for notifying the communication partner of successful reception of the data signal. 16 and a traffic monitoring unit 17 for monitoring the traffic volume of data transmitted from the communication partner (claims 1, 7, 8, and 9).
[0034]
When data is transmitted from the communication partner, the data receiving unit 15 receives the transmission data on the receiving side. Upon reception, the data receiving unit 15 notifies the traffic monitoring unit 17 of the size of the received data. The traffic monitoring unit 17 counts the data size notified from the data receiving unit 15 for a certain period of time, and calculates the traffic volume of the other party from the total amount of data that has arrived within the counting period and the time length of the counting period. If the calculated traffic volume exceeds a preset threshold, the traffic monitoring unit determines that the system is congested based on transmission data from the terminal, and notifies the confirmation signal transmitting unit 16 of the congestion. . The acknowledgment signal transmitting unit 16 transmits the congestion information notified from the traffic monitoring unit 17 to the other party together with the data reception acknowledgment when transmitting the reception acknowledgment signal to the communication partner. More specifically, one bit of the reception confirmation signal is reserved for congestion information. If "1", "congestion exists"; if "0", "congestion does not exist". Alternatively, in the case of “no congestion”, it may be simply “null” instead of “0” (claim 2).
[0035]
FIG. 4 shows an operation sequence of the transmitting side and the receiving side when the apparatus is not in the congestion state. When data is transmitted from the transmission side, the reception side that has received the data transmits a reception confirmation signal from the confirmation signal transmission unit 16. At this time, information indicating that there is no congestion state is carried and transmitted. The transmitting side that has received it immediately transmits the next data. When there is no congestion, the transmitting side continuously transmits as much data as possible, so that transmission traffic is not suppressed.
[0036]
FIG. 5 shows an operation sequence of the transmission side and the reception side in the congestion state. When data is transmitted from the transmission side, congestion information is transmitted simultaneously with the reception confirmation signal from the confirmation signal transmission unit 16 on the reception side, and the transmission side receiving the transmission time delays the transmission timing of the next data in time. Stagger. When the congestion information is continuously transmitted, the data transmission interval on the transmission side gradually increases, and transmission traffic is suppressed (claims 14, 15, and 16).
[0037]
In addition, the threshold for the traffic monitoring unit 17 to determine congestion is calculated by calculating the ratio of wireless terminals transmitting a data amount exceeding the threshold to all wireless terminals in the same system. Is changed (claims 6, 9 and 19). For example, if a large number of wireless terminals have a transmission data amount exceeding the threshold, it is refrained from setting the current threshold larger than this, and it is determined that it is better to change the current threshold to a smaller value. If only a small number of wireless terminals have a transmission data amount exceeding the threshold value, it is determined that there is no problem even if the current threshold value is set larger than this.
[0038]
As described above, since the threshold value is changed due to the increase or decrease of the transmission data amount in the same system, the transmission data amount is determined to be exceeding the threshold value, and the wireless terminal, which has been notified of the congestion information, performs the communication. In some cases, congestion information is not notified in the middle of the process, but information indicating that the user is not in a congestion state may be notified instead.
[0039]
FIG. 6 shows an operation sequence on the transmitting side and the receiving side in a case where the congestion state and the non-congestion state are mixed. When data is transmitted from the transmission side, congestion information is transmitted simultaneously with the reception confirmation signal from the confirmation signal transmission unit 16 on the reception side, and the transmission side receiving the transmission time delays the transmission timing of the next data in time. Stagger. When the congestion information is continuously transmitted, the data transmission interval on the transmitting side gradually increases, and transmission traffic is suppressed. As described above, when the threshold is changed during the communication and data is transmitted from the transmitting side, the receiving side that has received the data transmits a reception confirmation signal from the confirmation signal transmitting unit 16. At this time, information indicating that there is no congestion state is carried and transmitted. The transmitting side that has received it returns the transmission timing of the next data to the previous timing. At this time, in the example of FIG. 6, the point where the previous transmission timing is delayed by 2t is returned to the delay of t time. If the information indicating that there is no congestion is included in the reception acknowledgment signal received thereafter, the transmission timing is further returned to the time t before (claim 13). Thereby, the delay of the transmission timing is eliminated. Alternatively, when information indicating that there is no congestion information is received at a point where the transmission timing is delayed by nt time after receiving the information indicating that it is in the congestion state continuously n times, the transmission timing of the transmission timing is changed at a stretch. Control for eliminating the delay (returning to the original state) may be performed (claims 17 and 18).
[0040]
The former gradually returning method has an advantage that the fluctuation range of the transmission data amount can be suppressed to be small. In addition, the latter method has a merit that the throughput after the elimination of congestion can be greatly improved. Which method is applied is determined according to the operation status of the system.
[0041]
FIG. 7 and FIG. 8 show the results of computer simulations of the transmission characteristics when using the conventional method and the transmission characteristics when using the present invention, respectively. In FIG. 7 (conventional system) and FIG. 8 (present invention), the horizontal axis indicates the generated traffic (Mbps) of the wireless terminal # 2, and the vertical axis indicates the throughput (Mbps) of each wireless terminal. FIG. 9 shows the configuration and simulation parameters of the wireless access system used for the simulation.
[0042]
The wireless access system in the computer simulation includes one wireless terminal connected to the wired network and two wireless terminals (wireless terminal # 1 and wireless terminal # 2) accessing the wired network via the terminal. Be composed. In the computer simulation, the generated traffic of the wireless terminal # 1 is set to a constant value, the generated traffic of the wireless terminal # 2 is changed, and the influence of the generated traffic of the wireless terminal # 2 on the throughput of the wireless terminal # 1 is examined.
[0043]
When the conventional method is used, as shown in FIG. 7, when the traffic generated by the wireless terminal # 2 increases, the throughput of the wireless terminal # 1 decreases, even though the traffic generated by the wireless terminal # 1 is constant. I do. In this simulation model, the wireless line speed is 36 Mbps, and the bandwidth is used by two wireless terminals. Therefore, when the total traffic in the system exceeds the line capacity, the bandwidth of 18 Mbps per terminal is increased by each terminal. It is desirable to be able to use it, but it can be seen that when the conventional method is used, there is a problem that the throughput is reduced and the equality cannot be maintained even though the generated traffic of the wireless terminal # 1 is 8 Mbps.
[0044]
On the other hand, when the present invention is used, as shown in FIG. 8, the throughput of the wireless terminal # 1 is maintained at a constant value regardless of the traffic generated by the wireless terminal # 2. It can be seen that the influence can be eliminated and equality can be maintained.
[0045]
【The invention's effect】
As described above, by using the present invention, it is possible to avoid congestion that may occur on the receiving side in a wireless access system using a distributed control scheme. Also, a desired wireless band can be allocated to a certain transmission partner. Further, it is possible to equally allocate a wireless band to a plurality of wireless terminals.
[Brief description of the drawings]
FIG. 1 is a diagram showing a wireless access system according to an embodiment.
FIG. 2 is a diagram showing a functional configuration on a transmitting side of the wireless terminal according to the embodiment;
FIG. 3 is an exemplary view showing a functional configuration on a receiving side of the wireless terminal according to the embodiment;
FIG. 4 is a diagram showing an operation sequence on the transmission side and the reception side in a non-congestion state according to the embodiment;
FIG. 5 is a diagram showing an operation sequence on the transmission side and the reception side in a congestion state according to the embodiment.
FIG. 6 is a diagram showing an operation sequence on the transmission side and the reception side in a case where the state of congestion and the case of not being congested of the present embodiment coexist.
FIG. 7 is a diagram showing transmission characteristics when a conventional method is used.
FIG. 8 is a diagram showing transmission characteristics when the present invention is used.
FIG. 9 is a diagram showing a computer simulation model.
[Explanation of symbols]
# 1 to # 3, B wireless terminal 11 data transmission unit 12 traffic control unit 13 congestion information detection unit 14 reception unit 15 data reception unit 16 acknowledgment signal transmission unit 17 traffic monitoring unit

Claims (19)

In a wireless access system including a plurality of wireless data transmitting devices that transmit data via a wireless line and a wireless data receiving device that receives data transmitted from a wireless data transmitting device group,
The wireless data receiving device,
Means for monitoring the amount of transmission data for each wireless data transmission device,
When the monitoring means detects the wireless data transmitting apparatus that transmits a transmission data amount exceeding a threshold, means for transmitting congestion information notifying the fact to the wireless data transmitting apparatus,
The wireless access system according to claim 1, wherein the wireless data transmitting device includes a unit that receives the congestion information and adjusts a transmission data amount. 2. The radio access system according to claim 1, wherein said transmitting means includes means for mounting said congestion information in a part of a reception confirmation signal used for data reception confirmation. 3. The wireless access system according to claim 1, wherein said means for adjusting the amount of transmission data includes means for increasing or decreasing the amount of transmission data according to the frequency of inclusion of said congestion information during a predetermined number of receptions of said acknowledgment signal. The means for increasing or decreasing the transmission data amount includes:
Means for extending the transmission interval by a predetermined time each time the congestion information is included in the reception confirmation signal,
4. The radio access system according to claim 1, further comprising: means for restoring the transmission interval when the acknowledgment signal received after the transmission interval is extended does not include the congestion information. 5. The radio access system according to claim 4, wherein said restoring means comprises means for restoring a transmission interval by a predetermined time every time the reception confirmation signal not including the congestion information is received. Means for calculating a ratio of the wireless data transmitting device transmitting a data amount exceeding a threshold for all the wireless data transmitting devices in the same system,
The wireless access system according to any one of claims 1 to 5, further comprising means for changing a threshold according to the ratio. The wireless data receiving apparatus applied to a wireless access system including a plurality of wireless data transmitting apparatuses for transmitting data via wireless lines and a wireless data receiving apparatus for receiving data transmitted from a wireless data transmitting apparatus group At
Means for monitoring the amount of transmission data for each wireless data transmission device,
Means for transmitting, to the wireless data transmitting apparatus, congestion information for notifying when the monitoring means detects the wireless data transmitting apparatus that transmits a transmission data amount exceeding a threshold value. Wireless data receiving apparatus. 8. The wireless data receiving apparatus according to claim 7, wherein said transmitting means includes means for mounting said congestion information in a part of a reception confirmation signal used for data reception confirmation. Means for calculating a ratio of the wireless data transmitting device transmitting a data amount exceeding a threshold for all the wireless data transmitting devices in the same system,
9. The wireless data receiving apparatus according to claim 7, further comprising means for changing a threshold according to the ratio. The wireless data transmitting apparatus applied to a wireless access system including a plurality of wireless data transmitting apparatuses for transmitting data via a wireless line, and a wireless data receiving apparatus for receiving data transmitted from a wireless data transmitting apparatus group At
A wireless data transmission device that transmits a transmission data amount exceeding a threshold from the wireless data reception device, receives congestion information notifying the fact, and adjusts the transmission data amount. Data transmission device. The wireless data transmission device according to claim 10, wherein the means for adjusting the amount of transmission data includes means for increasing or decreasing the amount of transmission data according to the frequency of inclusion of the congestion information during a predetermined number of receptions of the acknowledgment signal. The means for increasing or decreasing the transmission data amount includes:
Means for extending the transmission interval by a predetermined time each time the congestion information is included in the reception confirmation signal,
The wireless data transmitting apparatus according to claim 11, further comprising: means for restoring the transmission time when the congestion information is not included in the reception confirmation signal received after the transmission interval is extended. 13. The wireless data transmitting apparatus according to claim 12, wherein the restoring unit includes a unit that restores a transmission interval by a predetermined time every time the reception confirmation signal not including the congestion information is received. In a wireless access method in which one wireless data receiving device receives wireless data transmitted from a plurality of wireless data transmitting devices via a wireless line,
The wireless data receiving device monitors the amount of transmission data for each of the wireless data transmitting devices, and when detecting the wireless data transmitting device that transmits a transmission data amount exceeding a threshold, transmits congestion information for notifying the wireless data transmitting device to the wireless data transmitting device. Send to data transmitter,
A wireless access method, wherein the wireless data transmitting device receives the congestion information and adjusts a transmission data amount. 15. The wireless access method according to claim 14, wherein the wireless data receiving apparatus mounts the congestion information on a part of a reception confirmation signal used for data reception confirmation. 16. The wireless access method according to claim 14, wherein the wireless data transmitting device increases or decreases a transmission data amount according to a frequency of the congestion information included in the predetermined number of receptions of the reception confirmation signal. The wireless data device, the reception confirmation signal extends the transmission interval by a predetermined time each time the congestion information is included, the reception confirmation signal received after the transmission interval is extended includes the congestion information 17. The wireless access method according to claim 14, wherein the transmission interval is restored when the transmission is not performed. 18. The radio access method according to claim 17, wherein a transmission interval is restored by a predetermined time each time the reception confirmation signal not including the congestion information is received. 19. The method according to claim 14, further comprising: calculating a ratio of the wireless data transmitting devices transmitting a data amount exceeding a threshold to all of the wireless data transmitting devices in the same system, and changing the threshold according to the ratio. The wireless access method according to any one of the above.

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