JP2006211362A - Access point and network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an access point capable of carrying out priority control in a finer unit with respect to an uplink direction in a wireless range in compliance with a wireless LAN system based on the IEEE 802.11e EDCA, and to provide a network system. <P>SOLUTION: The access point differently sets a CWmin value and a CWmax value designated by each access category denoting the traffic priority of an EDCA parameter by each SSID and sets SSIDs used by terminals 11, 12 differently. Thus, the access point can carry out the priority control in the finer unit than 4 stages of priorities which can be set to one SSID to enhance QoS. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an access point and a network system.

  In recent years, wireless LANs based on the IEEE 802.11 standard have spread, and large-scale wireless LAN networks have been built in public networks and corporate networks. Recently, a method of multiplexing virtual access points by using a small number of radio frequencies successfully has been studied (see Non-Patent Document 1, for example). Here, for example, as shown in FIG. 5, two BSSIDs are allocated on one accent point 200 so that a plurality of virtual access points can be seen from each of the terminal 201 and the terminal 202 which are network devices. To. In this way, a plurality of networks can be multiplexed and used while using the same radio channel.

  Currently, in IEEE 802.11, standardization for extending the MAC (Media Access Control) layer and providing QoS (Quality of Service) support is being promoted by IEEE 802.11 TGe (Task Group e). From this group, EDCA (Enhanced Distributed Channel Access) based on autonomous distributed control has been proposed as an access control method (see Non-Patent Document 2, for example).

  When the channel changes from busy to idle, EDCA allocates carrier sensing time (AIFS) for a certain period of time by traffic priority (ie, by access category). And if it is idle between AIFS, a random number will be generated within the range of 0 or more and CW (Contension Window) or less in order to avoid a collision, and if it is idle (Backoff) time idle based on the random value, it will be transmitted. I do. CW takes a value not less than CWmin and not more than CWmax according to the number of retransmissions. If the traffic has a high priority, the transmission waiting time based on the AIFS + backoff time is shortened, and transmission can be performed with priority.

  Here, FIG. 7A is a schematic diagram illustrating access point transmission processing. A similar process is performed at the terminal. FIG. 7B is a diagram illustrating an output waveform after transmission processing, and FIG. 7C is a diagram illustrating an example of an EDCA parameter. The EDCA parameters shown in (c) are made up of “Access Category”, “CWmin”, “CWmax”, “AIFSN”, and “TXOP Limit”. The four access categories (AC) are “AC_VO”, “AC_VI”, “AC_BE”, and “AC_BK”. “AC_VO” is mainly used for audio data, “AC_VI” is mainly used for video image data, “AC_BE” is mainly used for data other than audio data and video data, and “AC_BK” is mainly used. Is used for data that may be uttered by a large delay.

  In the example of (c), “2” is set in “AC_VO” and “AC_VI”, “3” is set in “AC_BE”, and “7” is set in “AC_BK”. CWmin and CWmax used for CW determination are “3”, “7” for “AC_VO”, “7”, “15” for “AC_VI”, “15” for “AC_BE” and “AC_BK”. , “1023” are set. TXOP Limit (continuous output possible time) is set to “3.264 ms” in “AC_VO”, “6.016 ms” in “AC_VI”, “0” in “AC_BE” and “AC_BK”, respectively. .

  The EDCA parameters used by the terminal are stored in the access point. When the terminal knows the EDCA parameters from the beacon or probe response transmitted from the access point and associates (connects) with the access point, as shown in FIG. EDCA parameters are set in the association response.

  In Wi-Fi alliance, Wireless Multimedia Enhancement (WME, see Non-Patent Document 3) is formulated as a subset of IEEE802.11e, and priority control is also performed on a device equipped with this WME based on the principle described above. Done.

IEEE Document IEEE802.11-03 / 154r1 "Virtual Access Points" IEEE P802.11e / D11.0, October 2004 "IEEE Standard for information technology Telecommunications and information exchange between systems Local and metropolitan area networks Specific requirements" 11-03-0504-07-000e-WMEredlined09Mar.doc

  However, in the conventional wireless LAN system based on IEEE802.11e EDCA, when priority control is performed with respect to the uplink direction of the wireless section, it can have four levels of priority according to the standard, but more detailed units (5 levels or more). There is a problem that it cannot be applied when priority control in (1) is desired.

  The present invention has been made in view of such circumstances, and an access point capable of performing priority control in fine units in the uplink direction of a wireless section in accordance with a wireless LAN system based on IEEE 802.11e EDCA And a network system.

The above object is achieved by the following configuration.
(1) An access point having an SSID (Service Set Identifier) used for a network device to be accommodated and having a BSSID (Basic Service Set Identifier) used corresponding to the SSID, and an EDCA corresponding to the SSID (Enhanced Distributed Channel Access) EDCA parameter storage means for storing a plurality of parameters with different contents and EDCA parameters stored in the EDCA parameter storage means for each SSID when accommodating a plurality of network devices EDCA parameter setting means.

(2) In the access point described in (1) above, the EDCA parameters include CWmin and CWmax used when determining a CW (Contension Window), and the EDCA parameter setting means is configured to determine the CWmin or CWmax. Store EDCA parameters whose values are different for each SSID.

(3) The access point according to (1) or (2) above and at least one network device that performs wireless communication with the access point.

  In the access point described in (1) above, the EDCA parameter is set to be different for each SSID, and the SSID to be used is different depending on the network device. Therefore, four-level priority control that can be set for one SSID. Therefore, priority control can be performed in finer units, and QoS can be improved.

  Since the access point described in (2) above has EDCA parameters with different CW values, priority control can be performed in units that are finer than the four levels of priority that can be set for one SSID.

  Since the network system described in (3) includes the access point described in (1) or (2) above, fine priority control is possible for each network device, and QoS A high network system can be constructed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a network system according to an embodiment of the present invention. In this figure, a network system according to the present embodiment includes an access point 10 connected to a communication network 500, a terminal 11 that is a network device that performs wireless communication with the access point 10 in accordance with the IEEE 802.11 wireless LAN standard, and 12. In this case, different SSIDs are used for the terminal 11 and the terminal 12, SSID A is used for the terminal 11, and SSID B is used for the terminal 12. Although the present embodiment describes a case where two terminals are accommodated in the same network, the number of terminals accommodated in the same network is not limited to two, but is arbitrary.

  FIG. 2 is a block diagram illustrating a schematic configuration of the access point 10. As shown in this figure, the access point 10 has a plurality of SSIDs (Service Set Identifiers) and BSSIDs (Basic Service Set Identifiers) which are MAC addresses for wireless LAN communication corresponding to the SSIDs. A transmission / reception control unit 101, two EDCA parameter storage units 102 and 103, and a management frame transmission / reception unit 104 are provided. The access point 10 sets SSIDs for the two terminals 11 and 12 to be accommodated. In this embodiment, since a difference is provided in the EDCA parameter corresponding to the SSID, the SSID used for the terminal 11 and the terminal 12 is changed according to the difference in priority. Here, for example, SSID A is set in the terminal 11 and SSID B is set in the terminal 12. The details of changing the SSID used for the terminal 11 and the terminal 12 according to the difference in priority will be described later.

  The terminal 11 uses a BSSID corresponding to SSID A for wireless LAN communication with the access point, and the terminal 12 uses a BSSID corresponding to SSID B for wireless LAN communication with the access point.

  The data transmission / reception control unit 101 wirelessly transmits a frame received from the communication network 500 to the terminal 11 or the terminal 12, and receives a frame transmitted wirelessly from the terminal 11 or the terminal 12 and transmits the frame to the communication network 500. The EDCA parameter storage units 102 and 103 store EDCA parameters used in the terminals 11 and 12. The management frame transmission / reception unit 104 transmits / receives a management frame including a beacon frame, a probe response frame, and an association response frame. In this case, the transmitted beacon frame, probe response frame, and association response frame include the EDCA parameters of the terminals 11 and 12 stored in the EDCA parameter storage units 102 and 103.

  3A and 3B are diagrams illustrating an example of the EDCD parameters. FIG. 3A illustrates EDCD parameters stored in the EDCD parameter storage unit 102, and FIG. 3B illustrates EDCD parameters stored in the EDCA parameter storage unit 103. FIG. In any case, the EDCA parameters are composed of “Access Category”, “CWmin”, “CWmax”, “AIFSN”, and “TXOP Limit” as in the conventional case. In this example, the same values are set in the EDCA parameter storage unit 102 and the EDCA parameter storage unit 103 for AIFSN and TXOP Limit (continuous output possible time). That is, “2” is set for “AC_VO” and “AC_VI”, “3” is set for “AC_BE”, and “7” is set for “AC_BK” for AIFSN, and TXOP Limit is set to “AC_VO”. Is set to “1.504 ms”, “AC_VI” is set to “3.008 ms”, “AC_BE” and “AC_BK” are set to “0”.

  On the other hand, different values are set for the generated random numbers in the EDCA parameter storage unit 102 and the EDCA parameter storage unit 103. That is, in the EDCA parameter storage unit 102, CWmin and CWmax are “7”, “15” for “AC_VO”, “15” for “AC_VI”, “31”, “AC_BE”, and “AC_BK”. 31 ”and“ 1023 ”are set. In the EDCA parameter storage unit 103, CWmin and CWmax are “3” for “AC_VO”, “7” for “AC_VI”, “15”, “15” for “AC_BE” and “AC_BK”. , “1023” are set. Conventionally, the EDCA parameter is common to all terminals accommodated in the network. However, in this embodiment, the CW value is different between the terminal 11 and the terminal 12, and the backoff time is set. Since the CWmin of the terminal 12 of SSID B is set smaller than that of the terminal 11 of SSID A, there is a higher probability that the backoff time will be shorter than that of the terminal 11, resulting in SSID. The uplink transmission of the B terminal 12 is preferentially performed. That is, at least five levels of priority control are possible as compared with the prior art which has only four levels of priority according to the standard. Thus, a difference is provided in the EDCA parameter corresponding to the SSID, and the SSID used for the terminal 11 and the terminal 12 is changed according to the difference in priority.

Next, a specific operation of the network system having the above configuration will be described.
≪Service image as a premise≫
Assuming that carriers and Internet service providers that provide paid services such as hotspots handle high-priority type terminals that pay high service charges and low-priority type terminals that pay low service charges, Furthermore, in order to share equipment, consider using one access point. However, high priority terminals and low priority terminals perform priority control using the IEEE 802.11e EDCA method in order to perform priority control for each application. In other words, a VoIP (Voice over Internet Protocol) packet that requires a real-time property for the terminal to realize an Internet phone or an IP phone, and a packet that does not require a real-time property such as HTTP (HyperText Transfer Protocol) or FTP (File Transfer Protocol). I want to preferentially send VoIP packets when I want to send them simultaneously. However, when a high-priority terminal and a low-priority terminal want to transmit VoIP at the same time, they want to transmit the VoIP packet of the high-priority terminal.

≪Preliminary setting≫
The access point 10 has two BSSIDs (MAC addresses) corresponding to two SSID A and SSID B, and has the function of a virtual AP (virtual access point) shown in the conventional literature. Furthermore, SED EDCA parameters are set in the respective EDCA parameter storage units 102 and 103 (see FIG. 3). Both the terminal 11 and the terminal 12 are terminals having the IEEE 802.11e EDCA function, and the SSID A and SSID B of the communication destination are used for these as described above.

★ (Operations until association of terminals 11 and 12 and acquisition of EDCA parameters (when terminals 11 and 12 are in passive scanning))
(A) The management frame transmission / reception unit 104 of the access point 10 periodically transmits a beacon frame including an EDCA parameter for SSID A stored in the EDCA parameter storage unit 102 (that is, does not specify a transmission destination). Send).

(A) Upon receiving the beacon frame including the EDCA parameter for SSID A, the terminal 11 knows that the access point 10 is compatible with IEEE 802.11e EDCA and the EDCA parameter.
(C) The terminal 11 makes an SSID A association request including an IEEE 802.11e EDCA request.

(D) The management frame transmitting / receiving unit 104 of the access point 10 transmits an association response including the EDCA parameter for SSID A stored in the EDCA parameter storage unit 102.
(E) Upon receiving the association response, the terminal 11 sets the EDCA parameter acquired from the access point 10 by the association response in the queue corresponding to the access category corresponding to the frame type.

  The terminal 12 is also associated with the access point 10 by performing the operations (a) to (e) with the SSID B.

★ (Data frame transmission operation)
(F) Assume that the terminals 11 and 12 use AC # VO for transmission of voice (VoIP) packets following the busy state.
(G) The terminal 11 performs carrier sense only for the time based on the AIFSN and then CW = 7. Therefore, after waiting for the backoff time corresponding to the random number × slot time selected from 0 to 7, Start sending frames.

  The terminal 12 performs carrier sense only for the time based on the AIFSN, and further CW = 3. Therefore, after waiting for the backoff time corresponding to the random number × slot time selected from 0 to 3, the terminal 12 Start sending.

(H) As shown in FIG. 4, as a result, the terminal 11 acquires the transmission right with a probability of 6/32, the terminal 12 acquires the transmission right with a probability of 22/32, and a collision occurs with a probability of 4/32. To do. In this case, the portion written as “11” is the transmission acquisition of the terminal 11, and the portion written as “12” is the transmission acquisition of the terminal 12. The acquisition number of the terminal 11 is “6”, and the acquisition number of the terminal 12 is “22”. Since the total number is “32 (= 8 × 4)”, the probability is 6/32 for the terminal 11 and 22/32 for the terminal 12 as described above. Further, the number of locations that collide is “4”, and the probability of collision is 4/32. In the case of a collision, the terminal 11 and the terminal 12 try to retransmit by selecting a new backoff time after increasing the CW according to the rule stipulated by IEEE 802.11.

  As described in (i), the SSID B terminal 12 with a small CWmin is more likely to have a shorter backoff time than the terminal 11 using SSID A, and as a result, SSID B The transmission in the uplink direction of the terminal 12 in which is used is preferentially performed. In other words, by setting different EDCA parameters for each SSID and setting different SSIDs to be used depending on the terminal, priority control can be performed in finer units than four levels of priority that can be set for one SSID. Become.

  As described above, according to the network system of the present embodiment, the CWmin value or CWmax value specified for each access category, which is the traffic priority of the EDCA parameter, is set differently for each SSID, and the terminals 11 and 12 Since the SSID to be used is set to be different, priority control can be performed in units that are finer than the four levels of priority that can be set for one SSID, and QoS can be improved.

  In addition, although it was the operation | movement when the terminals 11 and 12 are passive scans, when the terminals 11 and 12 are active scans, the above (a) and (b) are replaced with the following. In this case, the effect is the same.

(A) 'The terminal 11 transmits a probe request with SSID A.
(A) ′ The management frame transmitting / receiving unit 104 of the access point 10 that has received the probe request transmits a probe response including the EDCA parameter for SSID A stored in the EDCA parameter storage unit 102.

(A) 'The terminal 11 receives the probe response including the EDCA parameter for SSID A, and knows that the access point 10 is compatible with IEEE 802.11e EDCA and the EDCA parameter.

  Also, as shown in FIG. 5 of the prior art, when adopting a configuration in which the communication network is logically separated for each SSID, if different EDCA parameters are set for the communication network A and the communication network B, Enables priority control in units of communication networks.

  In the above embodiment, the IEEE 802.11e EDCA has been described as the priority control method. However, the same effect can be obtained by using Wireless Multimedia Enhancement (WME) formulated by Wi-Fi Alliance, which is a subset of IEEE 802.11e EDCA. can get.

  The present invention has an effect that priority control can be performed in finer units than the four priority levels that can be set for one SSID, such as IEEE 802.11e EDCA and WME established by Wi-Fi alliance, which is a subset thereof. Application to is possible.

1 is a block diagram showing a schematic configuration of a network system according to an embodiment of the present invention. The block diagram which shows schematic structure of the access point which comprises the network system of FIG. The figure which shows an example of the EDCA parameter memorize | stored in the EDCA parameter memory | storage part which comprises the access point of FIG. The figure for demonstrating the transmission right acquisition in each terminal which comprises the network system of FIG. Block diagram showing a schematic configuration of a conventional network system The figure which shows the communication before the data transmission between the access point and terminal in a network system Schematic diagram showing conventional access point transmission processing in a network system

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Access point 11, 12 Terminal 101 Data transmission / reception control part 102, 103 EDCA parameter memory | storage part 104 Management frame transmission / reception part 500 Communication network

Claims (3)

An access point having an SSID (Service Set Identifier) used for a network device to be accommodated and a BSSID (Basic Service Set Identifier) for identifying the network device,
EDCA parameter storage means for storing a plurality of different EDCA (Enhanced Distributed Channel Access) parameters corresponding to the SSID;
EDCA parameter setting means for setting EDCA parameters stored in the EDCA parameter storage means for each SSID when accommodating a plurality of network devices;
Access point with EDCA parameters include CWmin and CWmax specified for each access category.
The access point according to claim 1, wherein the EDCA parameter setting means stores EDCA parameters in which the value of the CWmin or CWmax is different for each SSID. The access point according to claim 1 or 2,
At least one network device in wireless communication with the access point;
A network system comprising:

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