KR200380716Y1 - Wireless local area network methods and components that utilize traffic prediction - Google Patents

Abstract

The present invention relates to a communication method, system, and component that uses traffic prediction as determined by a wireless transmit / receive unit (WTRU). The present invention is well implemented by predicting traffic in a wireless local area network (WLAN) between the WLAN access point (AP) and the WTRU, which begins by determining the traffic level at the WTRU. Traffic prediction information is sent by the WTRU to the AT when used in conjunction with the generation of commands sent to the WTRU to control by the WTRU access to the WLAN via the AP. The WTRU is preferably configured to receive and enforce instructions for adjusting the contention window that the WTRU uses to receive data and to send instructions on grants.

Description

WIRELESS LOCAL AREA NETWORK METHODS AND COMPONENTS THAT UTILIZE TRAFFIC PREDICTION}

The present invention relates generally to a wireless local area network (WLAN), and more particularly to a system and method for predicting traffic in a WLAN that is compatible with one or more standard families known as 802.11.

Wireless communication systems are known in the art. In general, a wireless communication system includes a communication station for transmitting and receiving wireless communication signals to each other. Depending on the type of system, the communication station is typically one of two types of wireless transmit / receive units (WTRUs), a subscriber unit comprising a base station or a mobile unit.

Here, the base station refers to devices including a base station, a Node B, a site controller, an access point, or other interface device in a wireless environment providing a WTRU that attempts a wireless connection to a network associated with the base station, and is limited to these devices only. It doesn't happen. WTRUs include personal communication devices such as network connected telephones, video phones and Internet telephones. WTRUs also include portable personal computing devices, such as laptops with PDAs and wireless modems with similar network capabilities. Portable or repositionable WTRUs are referred to as mobile units. In general, the base station is also a WTRU.

Typically, a network of base stations is formed where each base station can perform simultaneous wireless communication with a properly configured WTRU. Some WTRUs are configured to perform direct wireless communication with each other, i.e. without a relay connection through the base station and the network. In general, this is referred to as peer-to-peer wireless communication. If the WTRU is configured to communicate with other WTRUs, the WTRU may itself be configured as a base station to function as a base station. The WTRU is configurable for use in multiple networks with network and peer-to-peer communication capabilities.

One type of wireless system called WLAN is configurable to perform wireless communication with a WTRU equipped with a WLAN modem capable of peer-to-peer communication with a WTRU equipped with similar equipment. WLAN modems are currently integrated into the majority of common communication and computing devices by manufacturers. For example, mobile phones, PDAs and laptop computers have one or more WLAN modems built in.

A typical WLAN environment with one or more WLAN base stations, commonly called access points (APs), is built according to the IEEE 802.11 standard. Access to these networks usually requires user authentication procedures. The protocol of this system is now standardized in the WLAN technology area. One protocol framework is a family of IEEE 802 standards.

Basic Service Set (BSS) is the basic building block of IEEE 802.11 WLAN, which consists of WTRUs, commonly called stations (STAs). Basically, STA sets that can talk to each other may form a BSS. The plurality of BSSs are interconnected through a structural component called a distribution system (DS) to form an extended set of services (ESS). An access point (AP) is a station (STA) that provides access to the DS by providing a DS service and generally allows simultaneous access to the DS by a plurality of STAs.

Multiple transmission rates (and dynamic switching between rates) can be used to optimize throughput by the 802.11 standard. Slower speeds result in a more robust operating range in a noisy environment than fast speeds, and robust modulation characteristics that allow good operation. The faster the speed, the better the throughput. It is an optimization challenge to always choose the best (best) possible speed for a given coverage and interference condition.

The 802.11 standard specification rates for the various versions currently specified are listed in Table 1 as follows.

802.11 standard data rates Standard Support Speed (Mbps) 802.11 (original) 1,2 802.11a 6,9,12,18,24,36,48,54 802.11b 1,2,5.5,11 802.11g 1,2,5.5,6,9,11,12,18,24,36,48,54

For 802.11g, rates 6,9,12,18,24,36,48,54 Mbp use Orthogonal Frequency Division Modulation (OFDM). The choice of speed can affect performance, taking into account the system, user throughput, range, and fairness.

Typically each 802.11 device has a speed control algorithm implemented in a device that is uniquely controlled by that device. In particular, it has uplink (UL) speed control at the STA and downlink (DL) speed control algorithm at the AP. The speed switching algorithm is not specified in the standard. It depends on the STA (and AP) implementation.

The advent of rapid WLAN technology and the influx of cell deployments and users have created new challenges in consideration of network performance management and congestion avoidance. The present invention is to improve the quality of service (QoS) by reducing the chance of congestion by providing a practical method of traffic prediction for WLAN.

A communication method, system, and component are provided that utilize traffic prediction determined by a wireless transmit / receive unit (WTRU). The present invention is implemented by predicting traffic in a WLAN between a WTRU and a WLAN access point (AP) that begins by determining the traffic level at the WTRU. The WTRU is preferably configured to generate an association request that includes traffic level prediction. The related request is sent to an AP configured to evaluate the request, which depends in part on traffic level prediction. The AP is also configured to take action in response to the assessment. Such measures include the generation and transmission of a signal that accepts, rejects, or partially accepts a request. The WTRU is configured to receive and process the AP signal to obtain a communication connection to the AP in accordance with the action determined by the AP in response to the WTRU's associated request.

Traffic prediction is applied at different stages, such as association and transmission, and is applicable from uplink and downlink, such as from the access point (AP) side and the user's WTRU side. Based on the predicted traffic information, the AP can make more intelligent decisions about user acceptance and reduce collisions by increasing the efficiency of bandwidth usage.

The traffic prediction method is well implemented in the application layer and the media access control (MAC) layer to be applicable in all IEEE 802.11 protocols.

According to one aspect of the present invention, a wireless transmit / receive unit (WTRU) is configured for use in a WLAN having a traffic congestion control unit. The WTRU has a transceiver and an associated processing unit. The processing unit is configured to generate traffic prediction information. The transmitter is configured to embed traffic prediction information in a wireless communication frame sent by the WTRU to the controlling entity. The receiver is configured to receive a wireless communication frame from the controlling entity that includes an instruction responsive to the traffic prediction information sent to the controlling entity.

It is configured for use in an IEEE 802.11 compliant system and the transmitter is configured to embed traffic prediction information in the relevant request frame. The receiver is preferably configured to receive a response command that accepts or denies the relationship that was generated based on the internal traffic information transmitted in whole or in part. If the WTRU is configured to operate in an IEEE 802.11 compliant system, the transmitter is preferably configured to embed the request traffic prediction information in a transmit request (RTS) frame, and the receiver is configured to receive a contention window adjustment command of the management frame from the controlling entity. do.

The transmitter is configured to transmit data based on the contention window and the receiver may be configured to receive a command from the controlling entity, which may include a contention window adjustment command. In this case, the WTRU has a contention window control for the transmitter to adjust the contention window based on the transmission in response to the contention window adjustment command received from the controlling entity. The contention window control unit sets the default minimum contention window well to reflect the increased wireless communication congestion, and increases the minimum contention window in response to the contention window adjustment command received from the controlling entity.

In another form of the present invention, the WTRU is configured to perform traffic congestion control in a WLAN. The WTRU also has a transceiver and associated processing unit. The receiver is configured to detect traffic prediction information embedded in a wireless communication frame transmitted by another WTRU. The processing unit is preferably configured to evaluate the traffic prediction information received from the other WTRUs in combination with other communication traffic data to generate a response command. The transmitter is preferably configured to transmit a wireless communication frame that includes a command generated in response to another WTRU.

Such a WTRU is preferably configured to operate in an IEEE 802.11 compliant system as an access point AP. Accordingly, the receiver is preferably configured to detect traffic prediction information embedded in an associated request frame received from another WTRU. The processing unit is preferably configured to evaluate the traffic prediction information received in the relevant request frame from the other WTRU to generate an accept permission command, or a limited accept permission command or a rejection command. The transmitter is then configured to send the generated accept command to another WTRU.

The transmitter of the AP is preferably configured to send a data contention window adjustment command generated by the processing unit to the selected WTRU based on the traffic prediction information received from the plurality of WTRUs. The processing unit of the AP is configured to generate an instruction to increase the contention window size if the selected congestion level is determined in connection with evaluating the received traffic prediction information. The receiver of the AP is preferably configured to detect traffic prediction information embedded in a transmission request (RTS) frame sent from the WTRU and the transmitter is preferably configured to transmit a contention window adjustment command of the management frame.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the present invention will be described in more detail.

Abbreviation table

AP Access point CIF Performance information fields CTS Clear for transmission MAC Media access control QoS Quality of service RRM Radio resource management RTS Send request STA soup WLAN Wireless LAN WTRU Wireless transmit / receive unit

The terms base station, access point (AP), station (STA), WTRU, and mobile unit are used in a general sense as described above. The present invention provides a wireless access network having one or more networked base stations that provide wireless access services for WTRUs. The present invention is particularly useful when the mobile unit or mobile station is used in connection with a mobile unit or mobile station as it enters or passes through each area of geographical coverage provided by a base station or other AP. WTRUs may have integrated or installed wireless WLAN devices or Bluetooth devices such as 802.11 (a), 802.11 (b), 802.1 (g) to communicate with each other. However, the proposed design is applicable to any wireless system.

In FIG. 1, a WLAN is shown in which the WTRU communicates wirelessly through an access point (AP) 54, which may be connected to other network infrastructure, such as a network management station (NMS) 16. The AP 54 is shown as communicating with the WTRU 18, the WTRU 20, the WTRU 22, the WTRU 24, and the WTRU 26. Communication is coordinated and synchronized through the AP 54. This structure is also called Basic Service Set (BSS) within the WLAN background. In general, WLAN systems support WTRUs with different data as reflected in the above speed chart. In some cases, the AP is configured to support multiple types of WTRUs, such as 802.11 (b) compliant WTRUs and 802.11 (g) compliant WTRUs.

The inventors of the present invention have recognized that traffic prediction can be advantageously used by the AP to control the flow of wireless communication. Traffic prediction is the predicted traffic volume from the WTRU. Traffic volume includes load, traffic characteristics, traffic duration, and the like. One example of a load level is to categorize services into three categories: high, medium, and low. The traffic feature can be selected, for example, as burst traffic or constant traffic. The traffic duration can be specified as a long duration or a short duration.

As an example, a user playing an online game at the application layer will have a higher traffic volume than a user who periodically checks e-mail. However, different computer games may have different data demand characteristics. One game requires a relatively continuous stream of information, such as video streaming. Another game requires a relatively large amount of data, or burst data flow, to be communicated accidentally. It is possible for a user to play video streaming online games to provide traffic prediction of high continuous traffic. It is possible for a user to check e-mail to provide traffic prediction of low burst traffic.

Traffic prediction can be obtained in multiple ways at different communication layers. During transmission, the WTRU may measure transmission throughput as the total number of frames per second and use it as traffic prediction for the next period. When a user launches an application, the traffic volume associated with that application (web browsing, streaming video, etc.) is available as traffic prediction. Thus, the processing unit of the WTRU is preferably configurable to generate traffic prediction information based on these factors in a form that can be embedded in a transmission communication frame for detection by the AP.

User communication between the WTRU and the AP in the WLAN is performed as initially determined at the relevant stage, in whole or in part, after access authorization. In a related step, the AP may make a known decision based on the predicted traffic information according to the present invention.

In the current IEEE 802.11 standard, the relevant requirements require network access without providing a traffic profile. The inventors have recognized that the requesting WTRU 18 may have information regarding the type of traffic that can be transmitted or received and it is beneficial to provide this information to the AP 54 during the relevant phase. The AP 54 then uses the association with the radio resource management (RRM) acceptance control 56 to determine how to accept the WTRU 18 to the WLAN based on the predicted traffic signaled by the WTRU. The procedure is described below with reference to FIG.

When the WTRU 18 initiates an associated request, the WTRU 18 is configured to inform the AP 54 in the associated request frame 15 shown in FIG. 2 regarding the expected time and predicted traffic required for communication. The WTRU is well configured to report different traffic levels, such as low, medium, and high. The WTRU may also be configured to further report data flow characteristics, such as burst traffic or continuous traffic. The user interface allows the user to enter traffic features, for example, in consideration of applications such as e-mail, web browsing, gaming, netmeeting, and the like.

Traffic prediction reports may be mandatory or optional depending on the network implementation. However, if the WTRU optionally provides traffic prediction reports in related needs, the RRM of the AP 54 may be configurable to provide selectively defined good handling of these needs compared to requests that do not include traffic prediction reports. .

Once the AP 54 receives the relevant request 15 with the traffic prediction report from the WTRU 18, the AP 54 can make an intelligent decision based on that prediction. To this end, the AP 54 is preferably configured to determine acceptance, rejection or grant restriction access to the WTRU 18 in a manner that avoids network congestion in view of the received traffic prediction report.

According to the present invention, speed negotiation between the WTRU 18 and the AP 54 may be performed at the relevant stage. The AP 54 preferably includes an acceptance rate in the associated response frame 17 sent to the WTRU 18. If the acceptance rate is slower than the required rate, the WTRU is well configured to determine if it can accept the slow rate. For example, the AP may store traffic profiles for different types of WLAN cards used by the WTRUs in communication with the AP. Since these cards can be used by different WTRUs, WLAN cards can be ranked into different groups to differentiate each service. The AP may determine based on a historical record of the traffic profile with respect to different services.

The standards-related requirement format is defined in the family of 802.11 standards. As shown in FIG. 3, the standard related request format 30 includes a frame body 34 including a media access control (MAC) header portion 32 and a function information field (CIF) 36. The CIF 36 is divided into a function information field 36a and a reserved field 36b. In order for the WTRU to inform the AP of its traffic profile, the WTRU preferably uses a portion 38 of the "reserved field" 36b in the CIF 36 of the associated request frame 30.

4 shows an example of the AP decision processing in the associated phase using the traffic prediction information. In this embodiment, it is assumed that all WTRUs have the same priority and the AP is designed to pay more attention when accepting high traffic users. The AP decision may be different in different implementations.

In the embodiment of FIG. 4, the AP preferably associates an associated request from the WTRU with any of the low, medium, or high prediction levels communicated in the “reserved field” 36b of the CIF 36 of the standard associated request frame 30. Receive The AP handles the request to accept or reject the WTRU base or communication prediction, the AP capability, the AP traffic load and, if the load is large, whether the load is a burst load. 4 provides an example decision tree of choosing to accept or reject a WTRU based on these factors.

The present invention can also be advantageously used after the WTRU has obtained a connection from the AP. 5 shows a preferred method when traffic prediction information is used to maintain efficient bandwidth utilization. The AP is preferably configured to make a decision to prioritize access of different users to the network based on the predicted traffic information to obtain fairness.

In the embodiment of FIG. 5, the WTRU transmits data from the WTRU to the AP using a Tx / CTS procedure. The WTRU informs the AP of the traffic profile in the RTS frame transmitted in step 40. In response, the AP provides the CTS signal at step 42 including a duration for data transmission. The WTRU then transmits data in step 44 according to the CTS and after receiving the data, the AP transmits an acknowledgment (ACK) signal in step 46.

The mechanism for changing access is the frequency at which the WTRU can access the medium by advising the WTRU (using a MAC management frame) to advise the WTRU to change the size of the contention window (CW) or change the backoff timer. It is a mechanism to change the. Thus, in addition to configuring the WTRU to determine and transmit traffic prediction information, the WTRU is well configured by variable contention window control to accept commands from the AP to adjust the WTRU contention window.

In the case of packet data transmission, the random backoff time of each packet is normally selected constantly between 0 and CW-1, and CW is a contention window value. The CW depends on the number of previous transmission failures for that packet. In the first transmission, CW is set to the value CWmin. That is, the minimum contention window is set. After each transmission fails, the CW typically doubles to the maximum value CWmax. After a successful transmission, the CW is typically reset to CWmin for the next packet. For systems compatible with the IEEE 802.11 (b) standard, the CWmin and CWmax values are designated as 32 and 1024 of 802.11b.

Instead of a WTRU with a fixed CWmin, the WTRU preferably has a relatively low default CWmin with the ability to reset CWmin in response to traffic control signals from the AP. If the overall traffic condition is high, CWmin is increased to avoid excessive collisions and backoff. If all of the traffic conditions are low, the WTRU preferably uses the default CWmin setting to avoid unnecessary idle airtime during periods when there are no stations to transmit.

5 illustrates an example of the operation. If the AP detects congestion at 47, the AP transmits a signal to any WTRU at step 48 to increase the contention window (CW) size or backoff timer. If the WTRU has the collision shown in step 49, the WTRU will wait long periods before attempting to transmit again by initiating a new RTS 40 '. In this way, the congestion situation is alleviated.

6 shows an example of AP flow control during a normal transmission phase. In FIG. 6, the AP receives an RTS frame with a traffic profile from the WTRU and stores the profile for later use. If the AP is not in a congestion situation, the AP responds to the CTS frame of the WTRU. However, in a congested situation, the AP uses the stored profile of all the WTRUs in communication to determine which WTRU is using the maximum bandwidth and determines that it is WTRUy. If the WTRUy is a WTRU using the maximum bandwidth (ie, WTRUx = WTRUy), the AP transmits a management frame to increase the contention window of the WTRUx. Otherwise, the AP sends a CTS frame to the WTRUx and then transmits a management frame to increase the contention window of the WTRUy. AP flow control may be triggered by means other than a timer, such as receiving a RTS with traffic prediction.

Although described in the preferred embodiment combining the features and elements of the present invention, each feature or element may be available alone (without other features and elements of the preferred embodiments) or with or with other features and elements of the present invention. Available in various combinations without

According to the configuration of the present invention, by using multiple transmission rates, it is possible to optimize throughput compatible with the 802.11 standard and always select the best (best) possible speed for a given coverage and interference condition.

1 is a system schematic diagram illustrating WLAN communication.

2 shows an overview of a system according to the present invention.

3 is a related request frame structure diagram according to the present invention;

4 is a flowchart showing an example of AP determination performed in a related step according to the present invention;

5 is a signal transmission flowchart illustrating the operation of the present invention.

6 is a flowchart showing an example of AP flow control according to the present invention;

Claims (11)

A wireless transmit / receive unit configured for use in a WLAN having a traffic congestion control using a predetermined radio frame format, A transceiver configured to transmit and receive wireless communication in a predetermined frame format, A processing unit, coupled to the transceiver, configured to process the received communication frame and format information in a frame for transmission; The processing unit is configured to generate traffic prediction information and embed the traffic prediction information in a wireless communication frame, The transmitter is configured to transmit a wireless communication frame to the controlling entity, the frame comprising a frame with embedded traffic prediction information, And the receiver is configured to receive a radio communication frame from a control entity that includes an instruction responsive to traffic prediction information embedded by the processing unit in a frame transmitted to the control entity. 2. The system of claim 1, configured to operate in an IEEE 802.11 compliant system, wherein the processing unit is configured to embed traffic prediction information in an associated request frame, and the receiver relate in whole or in part based on transmitted embedded traffic prediction information. And receive a response command to approve or disapprove. 10. The system of claim 1, configured to operate in an IEEE 802.11 compliant system, wherein the transmitter is configured to transmit a communication frame based on a contention window, and the receiver receives a command from the control entity that may include a contention window adjustment command. And the WTRU further comprises a contention window control for adjusting a contention window that the transmitter transmits in response to a contention window adjustment command received from the control entity. 4. The WTRU of claim 3 wherein the contention window control unit sets a default minimum contention window and increases the minimum contention window in response to a contention window adjustment command received from the control entity reflecting increased wireless communication congestion. . 4. The system of claim 3, configured to operate in an IEEE 802.11 compliant system, wherein the processing unit is configured to embed traffic prediction information in a transmission request (RTS) frame, and the receiver commands a contention window adjustment command of a management frame from the control entity. And a wireless transmit / receive unit configured to receive a signal. A base station configured for use in a WLAN that uses a predetermined radio frame format and is configured to implement traffic congestion control. A transceiver configured to transmit and receive wireless communication in a predetermined frame format, A processing unit, coupled to the transceiver, configured to process the received communication frame and format information in a frame for transmission; The processing unit is configured to detect traffic prediction information embedded in a wireless communication frame received from a wireless transmit / receive unit (WTRU) to the receiver, The processing unit is configured to generate a response command and evaluate the traffic prediction information received from the WTRU in combination with other communication traffic data such that the generated response command is included in a formatted communication frame, The transmitter is configured to transmit a wireless communication frame that includes a command generated in response to the WTRU. 7. The system of claim 6, configured to operate as an access point AP in an IEEE 802.11 compliant system, wherein the processing unit detects traffic prediction information embedded in an associated request frame received from the other WTRU, and from the WTRU in an associated request frame. Evaluate the received traffic prediction information and generate an admission grant command or a limited admission grant command or an admission denial command, wherein the transmitter is configured to send an admission command generated by the processing unit to the WTRU. . 7. The base station of claim 6 configured to operate as an access point (AP) in an IEEE 802.11 compliant system. 9. The base station of claim 8, wherein the transmitter is configured to send a data contention window adjustment command to a selected WTRU generated by the processing unit based on traffic prediction information received from multiple WTRUs. 10. The base station of claim 9, wherein the processing unit generates an instruction to increase the contention window size when determining the selected congestion level in connection with evaluating the received traffic prediction information. 10. The apparatus of claim 9, wherein the processing unit is configured to detect traffic prediction information embedded in a transmission request (RTS) frame transmitted from a transmitting WTRU, and wherein the transmitter is configured to transmit a contention window adjustment command in a management frame. Base station.