System and method for utilizing stored higher layer information

[0001] SYSTEM AND METHOD FOR UTILIZING STORED HIGHER LAYER INFORMATION [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to digital communications, and more specifically, to a system and method for using stored higher layer information.

The technical standards and concomitant technologies of the IEEE 802.11 family, also referred to as Wi-Fi, are evolving toward a service-centric model of connectivity that devices connect for specific purposes. An intentional connection is triggered by an application looking for a network and / or a peer device that supports a particular service. Examples of such services include file sharing, printing, media streaming, sensor information, and the like.

An exemplary embodiment of the present disclosure provides a system and method for using stored higher layer information.

According to an exemplary embodiment of the present disclosure, a method for operating a station during a discovery process is provided. The method includes the steps of: transmitting, by the station, a first layer 2 frame to an access point (AP), the first layer 2 frame comprising first layer information, A first version number associated with the first higher layer information and an identifier of a protocol associated with both the first higher layer information and the first version number; 2 frame including an indication that the version number is equal to the first version number, and determining, by the station, whether to perform the network selection process according to the first higher layer information .

According to another exemplary embodiment of the present disclosure, a method for operating an access point is provided. The method includes receiving, by the access point, a first layer 2 frame from a station, the first layer 2 frame including a first version number associated with the first higher layer information, 1 version number associated with the first higher layer information, - obtaining, by the access point, a second version number associated with the second higher layer information from the server, And transmitting by the access point a second layer 2 frame to the station if the first version number matches the second version number, , And the second layer 2 frame includes an indication that the first version number matches the second version number.

According to another exemplary embodiment of the present disclosure, there is provided a station adapted to perform a discovery process. The station comprising: a processor; And a computer readable storage medium storing a program executed by the processor. Wherein the programming includes providing a first layer 2 frame including an identifier of a protocol associated with both the first version number and the first version number associated with the first higher layer information, Receives a second layer 2 frame from the AP, the second layer 2 frame including an indication that a second version number associated with the second higher layer information is the same as the first version number, And to determine whether to perform the selection process.

According to another exemplary embodiment of the present disclosure, an access point adapted to participate in the discovery process is provided. The access point comprising: a processor; And a computer readable storage medium storing a program executed by the processor. Wherein the programming comprises receiving from the station a first layer 2 frame comprising a first version number associated with the first higher layer information and an identifier of the protocol associated with both the first higher layer information and the first version number, Obtaining a second version number associated with the second higher layer information from the server, determining whether the first version number matches the second version number, and if the first version number matches the second version number And to transmit to the station a second layer 2 frame containing an indication that the first version number matches the second version number.

According to another exemplary embodiment of the present disclosure, a method is provided for operating a communication device adapted to transmit a frame. The method comprises: generating, by the communication device, a layer 2 frame comprising at least one common ad group (CAG) tuple field, the at least one CAG tuple field having a CAG version number A version field, a scope field including a scope value, and an identifier field of an advertisement protocol; And transmitting the layer 2 frame by the communication device.

According to another exemplary embodiment of the present disclosure, a station is provided. The station comprising: a processor; And a computer readable medium storing a program executed by the processor. Wherein the programming comprises generating a layer 2 frame comprising at least one common ad group (CAG) tuple field and transmitting the layer 2 frame, wherein the at least one CAG tuple field comprises a CAG version number A CAG version number field including a range value, a range field including a range value, and an identifier field of an advertisement protocol.

According to a first further exemplary embodiment of the present disclosure, a station is provided. The station comprises:

Means for transmitting a first layer 2 frame to an access point (AP), the first layer 2 frame having a first version number associated with first layer information, And an identifier of a protocol associated with both the first higher layer information and the first version number;

Means for receiving a second layer 2 frame from the AP, the second layer 2 frame including an indication that a second version number associated with the second higher layer information is equal to the first version number; And

And means for determining whether to perform the network selection process according to the first higher layer information.

In a first aspect according to the first further example, the station comprises means for obtaining the first higher layer information and the first version number; And means for storing the first higher layer information and the first version number.

In a first aspect according to the first further example or in a first aspect according to the first further example, the first version number is included in an advertisement protocol element in the first layer 2 frame.

In a first aspect according to a third aspect or a first additional example according to the first additional example, the first version number is a common advertisement group (CAG) number element in the first layer 2 frame, .

In a first aspect according to the fourth further aspect of the first further example, the first layer 2 frame further comprises a query request for the second higher layer information.

In any of the previous aspects according to the fifth aspect or the first additional example according to the first additional example, the first layer 2 frame is an IEEE 802.11 GAS Initial Request frame, and the second layer 2 frame IEEE 802.11 GAS Initial Response frame.

According to a second further exemplary embodiment of the present disclosure, an access point is provided. The access point comprising:

Means for receiving a first layer 2 frame, the first layer 2 frame comprising a first version number associated with the first higher layer information and an identifier of a protocol associated with both the first higher layer information and the first version number -;

Means for obtaining a second version number associated with the second higher layer information from the server;

Means for determining whether the first version number and the second version number match; And

And means for transmitting a second layer 2 frame to the station if the first version number and the second version number match,

The second layer 2 frame includes an indication that the first version number matches the second version number.

In a first aspect according to a second further example, the access point comprises means for transmitting a third layer 2 frame to the station if the first version number and the second version number do not match, The layer 2 frame includes an indication that the first version number and the second version number do not match.

In a first aspect according to a second or a second further example according to a second further example, the access point receives a fourth layer 2 frame from the station, the fourth layer 2 frame comprising a query request, ; Means for transmitting the query request to the server, receiving a query response from the server, and transmitting a fifth layer 2 frame to the station, wherein the fifth layer 2 frame comprises the query response.

In any one of the first aspect and the second aspect according to the third or the second additional example according to the second further example, the access point may be configured such that if the first version number and the second version number do not match, Retrieving a query request from a first tier 2 frame, forwarding the query request to the server according to an identifier of the protocol, receiving a query response from the server, and transmitting, to the station, And means for transmitting layer 2 frames.

In any one of the first aspect, the second aspect and the third aspect according to the fourth or second further example according to the second further example, the indication that the first version number and the second version number are identical, 2 & lt; / RTI & gt; layer 2 frame.

According to a third further example, a station is provided. The station comprises:

Means for generating a layer 2 frame comprising at least one common ad group (CAG) tuple field, the at least one CAG tuple field comprising a CAG version number field containing a CAG version number, A scope field containing an identifier, and an identifier field of an advertising protocol; And

The means for transmitting the layer 2 frame

.

In a first aspect according to the third additional example, the CAG version number field is 8 bits in size.

In a second aspect according to the third additional example, the identifier field of the advertisement protocol is a partial advertisement protocol identifier field including a partial advertisement protocol identifier, the size is 5 bits, and the partial advertisement protocol identifier is the CAG version number And a 5-least significant bit among the advertisement protocol identifiers of the advertisement protocol associated with the range value in the same CAG tuple field. The range field is 3 bits in size.

In a third aspect according to the second aspect according to the third additional example, the advertisement protocol is an access network query protocol (ANQP), and the partial advertisement protocol identifier field includes a value of zero.

In a fourth aspect according to the second aspect according to the third further example, the advertisement protocol is a registered location query protocol (RLQP), and the partial advertisement protocol identifier field contains a value of 4.

The practice of the embodiments described above is that the AP is initiated by the STA and the server supporting the higher layer service if the upper layer information version number stored by the STA is equal to the current upper layer information version number of the server By allowing the specified query request to be short-circuited, the STA can provide a fast response and the STA can make quick decisions such as network selection decisions.

In addition, by using signaling means outside the container field that carries an upper layer query request or query response (e.g., by using an advertisement protocol element or a CAG number element to carry the layer information version number, (By using the status code value to indicate that the stored upper layer information version number is the same as (or is different than) the current upper layer information version number of the server supporting the upper layer service) A tradition that does not need to understand the contents of.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present disclosure and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, 1 illustrates a first exemplary communication system according to an exemplary embodiment described herein. Figure 2 illustrates a second exemplary embodiment that emphasizes GAS and ANQP operation in accordance with the exemplary embodiment described herein. 3A shows an example frame body of a GAS initial request frame. Figure 3B shows an example format of the advertisement protocol element. Figure 4 shows the common format of ANQP elements. Figure 5 shows a list of example ANQP elements. 6 shows an example format of a query list ANQP element. FIG. 7 shows an example frame body format of a GAS initial response frame. Figure 8 shows an example format of a CAG number element. Figure 9 shows an example format of the CAG ANQP element. FIG. 10 illustrates a message exchange flow diagram 1000 highlighting exemplary message exchange during a network discovery process occurring among STA, AP, and ANQP in accordance with the illustrative embodiment described herein. 11 illustrates the format of an example advertisement protocol element in the case where the advertisement protocol element is included in the GAS initial request frame according to the exemplary embodiment described herein. FIG. 12 illustrates a message exchange flow diagram highlighting exemplary message exchanges during network discovery, service discovery, or information discovery processes that occur among STAs, APs, and servers in accordance with the illustrative embodiment described herein. FIG. 13 illustrates a network discovery, service discovery, or information discovery process that occurs among STAs, APs, and servers when the STA is also optimized to effectively conserve network capacity using signaling overhead, according to the exemplary embodiment described herein. Lt; RTI ID = 0.0 & gt; exchange of messages. 14A shows a flow diagram of a first example task 1400 that occurs in an STA participating in a network discovery, service discovery, or information discovery process in accordance with the illustrative embodiment described herein. FIG. 14B shows a flow diagram of a second exemplary operation 1450 that occurs in a STA participating in a network discovery, service discovery, or information discovery process in accordance with the illustrative embodiment described herein. 15A shows a flow diagram of a first example task 1500 that occurs at an AP participating in a network discovery, service discovery, or information discovery process in accordance with the illustrative embodiment described herein. 15B illustrates a flowchart of a second example operation 1550 that occurs at an AP participating in a network discovery, service discovery, or information discovery process in accordance with the exemplary embodiment described herein. 16 illustrates an exemplary CAG number IE 1600 that includes the ID of the advertising protocol associated with the CAG version number in accordance with the illustrative embodiment described herein. FIG. 17 illustrates an exemplary alternative CAG number IE according to an exemplary embodiment described herein. FIG. 18 shows a flow diagram of an exemplary task 1800 that occurs in a communication device that transmits a frame containing a CAG number IE in accordance with the illustrative embodiment described herein. Figure 19 illustrates a computing platform that may be used, for example, to implement the apparatus and methods described herein, in accordance with an embodiment.

The operation of the present exemplary embodiment and its structure is described in detail below. It should be understood, however, that the present disclosure can provide many applicable exemplary embodiments that can be embodied in a wider variety of specific contexts. The illustrated exemplary embodiments are merely examples of the specific structure of the present disclosure and the manner of operating the present disclosure, and are not intended to limit the scope of the present disclosure.

One embodiment of the present disclosure relates to using stored higher layer information. For example, a station may transmit a first layer 2 frame containing a first version number associated with the first higher layer information and an identifier of the protocol associated with both the first higher layer information and the first version number, (AP), receives a second layer 2 frame from the AP, the second layer 2 frame including an indication that the second version number associated with the second higher layer information is the same as the first version number, And determines whether to perform the network selection process according to FIG.

The present disclosure will be described with respect to a communication system supporting an exemplary embodiment in a particular context, i.e., a service-oriented connection and a pre-association for discovering the service before establishing the connection. The present disclosure relates to a method and apparatus for supporting IEEE 802.11ai, IEEE 802.11af, IEEE 802.11aq, WiFi Alliance (WFA) Optimized Connectivity Experience (OCE) specifications, WFA Compliant communication systems such as those conforming to the TV White Space (TVWS) specification, the WFA Application Service Platform-Infrastructure (ASP-I) specification, the Third Generation Partnership Project (3GPP) Device-to- Standard, and standards-compliant communication systems.

1 illustrates a first exemplary communication system 100. As shown in FIG. Communication system 100 includes an access point (AP) 105 that serves a plurality of devices, such as device 110, device 112, device 114, device 116, and device 118 . The AP may also be generally referred to as a base station, a communications controller, a controller, a NodeB, an evolved NodeB (eNB), and the like. The device may also be generally referred to as a station (STA), a user equipment (UE), a mobile station, a mobile, a user, a subscriber, a terminal, In the first communication mode, the device can communicate via the AP 105 by sending a frame to the AP 105, which forwards the frame to the intended recipient. In the second communication mode, the first device may transmit the frame directly to the second device without going through the AP 105. [

Although a communication system can use multiple APs capable of communicating with multiple stations, only a single AP and multiple stations are shown in FIG. 1 for simplicity.

The STA typically performs network discovery and selection (NDS) procedures before accessing the services provided by APs and APs. The NDS procedure is performed prior to the authentication and association procedure, and usually involves discovery of the AP.

The IEEE technical standard 802.11u allows an STA to establish an access network and / or a subscription service provider network (SSPN), which is connected to the AP, before associating with the AP so that STAs can make the pragmatic decisions about network selection. (ANQP) and a generic advertisement service (GAS) frame in order to discover the characteristics, services, and parameters of the network. The GAS transport mechanism has been extended to support additional advertising protocols such as medium-independent handover (MIH) defined in IEEE standard 802.21 and registered location query protocol (RLQP) defined in IEEE 802.11af fixes. Currently, the IEEE 802.11aq project is also considering using GAS to support pre-association discovery protocols for service information discovery before association.

2 illustrates a second exemplary communication system 200 that emphasizes GAS and ANQP operation. First, the user of the device initiates an attempt to connect to Wi-Fi, and the user's device scans for available access points, also referred to as WiFi hotspots. In IEEE 802.11u, the GAS frame is used to provide Layer 2 transmission of query protocol data and query response data of the advertisement protocol between the client on the user's device and the AP connected to the server on the network before authentication and association with the AP. do. The query request data and the query response data are also typically transmitted between the AP and the server using a sie-layer protocol such as Diameter or Remote Authentication Dial-In User Service (RADIUS) and IP transmission. In IEEE 802.11u, ANQP is a specific advertising protocol used to discover different features of an access network and available services. After receiving the ANQP query response data, the user's device selects a specific AP, and then continues the authentication and association process to establish a connection with the AP.

Communication system 200 may be an example of a Wi-Fi compliant communication system. Communication system 200 may use communication services and protocols, such as GAS and ANQP, to support operations involving scanning and network selection. In general, the GAS frame is used to provide a connection between the terminal and the server in a communication system, such as the communication system 200, before or after association with authentication (e.g., of the terminal) Can be used to provide Layer 2 transmission. Typically, the ANQP may be used to discover different features and / or services of the communication system. The device compares information about the network or access point to select, for example, the one best suited to associate. The device can continue the authentication process

Typically, a station may be used to refer to any of the devices shown in FIG. 2 (such as devices 205, 207, 209), and may communicate with a communication system 200 (such as a Wi-Fi interface) Other devices having interfaces may include, but are not limited to, cellular telephones, laptop computers, tablets, smart sensors, handhelds, or consumer electronic devices. Some or all of the stations may also interact with other types of communication systems, such as a cellular network, Bluetooth, proprietary, and the like.

The AP 210 and one or more stations may form a basic service set (BSS), which is a basic building block of a Wi-Fi communication system. The BSS may be identified by a service set identifier (SSID), which is a set identifier, and may be broadcast by an AP of the BSS, such as the AP 210. [ AP 210 may communicate with AP controller and / or ANQP server, which may be co-located with AP 210 or may not be co-located. The AP 210 may be coupled to a service provider network 215 coupled to one or more roaming hubs 220. The roaming hub 220 may be coupled to a home location register (HLR) Roaming hub 220 and HLR 225 provide support for device mobility, i. E., Roaming.

The GAS frame has been specified since 802.11u and is now integrated within the IEEE standard 802.11-2012. The GAS frame includes a GAS initial request frame, a GAS return request frame, a gas initial response frame, and a GAS return response frame. The GAS initial request frame is sent by the requesting STA to initiate the query process. As shown in FIG. 3A, the GAS initial request frame body includes a category field 305 and an action field 310 that together indicate that the frame is a GAS initial request frame, The length of the query request field 360 indicating the length of the Dialog Token field 315, the advertisement protocol element 320, the query request field 360 and the query request field 260 including the sequence number as an octet Field 340 as shown in FIG.

The advertisement protocol element 320 is used to indicate an advertisement protocol associated with the query request included in the GAS initial request frame. When included in the GAS initial response or GAS return response frame, the advertisement protocol element is also used to indicate an advertisement protocol associated with the query response contained in the GAS initial response or GAS return response frame. As shown in FIG. 3B, the advertisement protocol element 320 includes a Query Response Info field 325 and an advertisement protocol ID field 331. The advertisement protocol ID field 331 includes an identifier specified for the corresponding advertisement protocol. The query response information field 325 is a 1-octet field composed of a 7-bit Query Response Length Limit subfield 327 and a 1-bit PAME-BI subfield 329. The standard 802.11-2012 specifies that when the advertisement protocol element is included in the beacon, probe response, GAS initial response, or GAS return response frame, the query response length limit sub-field is included in one or more GAS return response frames, Field, and when the advertisement protocol element is included in the GAS initial request frame, such as the advertisement protocol element 320, the query response information field 325 of the entire one octet is set to a value of 0 ) Specifies that the responder ignores these fields upon receipt.

The query request field 360 is a generic container that carries the query request of the advertising protocol and typically uses Layer 2 transport services located above layer 2 in the protocol stack and provided by the GAS frame. Thus, the AP receiving the GAS request frame does not need to interpret the contents of the query request field 360. The AP can retrieve the contents of the query request field 360 based on the value in the query request length field 340 and can use the protocol and transmission means established between the AP and the server to identify the advertisement protocol ID field 331, And delivers the content to the corresponding advertisement protocol server based on the value in the advertisement protocol server. In normal deployment, the AP is connected to the server via a wired connection with an IP-based transmission. Examples of upper layer protocols used between AP and server include Diameter and RADIUS.

In the case of ANQP, the query request contained within the query request field 360 typically includes a query list ANQP element that provides a list of identifiers of ANQP elements that the requesting STA wishes to receive. The ANQP element is defined to have a common format consisting of an information ID field of 2 octets, a gyri field of 2 octets, and a variable-first element-specific information field, as shown in FIG. 4 . Figure 5 lists some example ANQP elements defined in 802.11-2012. Most of the ANQP elements listed in FIG. 5 are used to form the ANQP response. Query List The ANQP element is one exception and it is used to form an ANQP query request. Other advertisement protocols may define an element dedicated to a protocol having a common format similar to that shown in Fig. For example, the 802.11af revision defined several RLQP-elements specific to RLQP.

The format of the query list ANQP element is shown in FIG. As shown in FIG. 6, the query list ANQP element includes an information ID (Info ID) field 610 including a value corresponding to the query list ANQP element defined in FIG. 5, a field Such as ANQP query ID field 630 and ANQP query ID field 640, each of which includes the information ID of the ANQP element requested by the STA, and a length field 620 indicating the length in octets, Field. Including the information ID in the query list ANQP element declares that the STA performing the ANQP query request wants to receive the ANQP element corresponding to the information ID in the ANQP query response.

After delivering the query request to the corresponding ad protocol server, the AP may receive a query response from the server. If the query response size is within the size constraint of a single GAS initial response frame, the AP may use the GAS initial response frame to carry the query response to the requesting STA. The query process can then be terminated. On the other hand, the AP breaks up the large query response into a plurality of GAS return response frames and requests the STA to send a GAS return request frame to receive a plurality of GAS return response frames to retrieve all fragments of the query response. To invite, it sends a GAS initial response frame that has a non-zero return delay value but does not contain any part of the query response. The STA then transmits the GAS Return Request frame, correspondingly receives the GAS Return Response frame, and repeats these steps until a GAS Return Response frame carrying the last segment of the query response is received. The STA can then reassemble the query response. The query process can then be terminated. The AP does not need to interpret the content of the query response received from the ad protocol server. The AP retrieves the contents of the query response, decomposes it if it is large, and sends it to the requesting STA using the GAS initial response frame or one or more GAS return response frames.

7 shows the frame body of the GAS initial response frame. 7, the GAS initial response frame body includes a category field 705 and an action field 710 that together indicate that the frame is a GAS initial response frame, and an action field 710, obtained from the dialog token field of the corresponding GAS initial request frame A status code field 720 indicating a status of a corresponding query process, a return delay field 730 including a return delay value, a advertisement protocol element 720, 320, and a query response length field 750. The query response length field 750 includes a query response length field 750, The GAS initial response frame body may optionally include a query response field 760. The value of 0 included in the query response length field 750 indicates the absence of the query response field 760. A non-zero value included in the query response length field 750 indicates the existence of the query response field 760 and its length in octets.

Since the service characteristics and parameters of the access network can be kept unchanged for a long time and because the STA can visit the same access network or subscriber service provider network (SSPN) every day through the same AP and AP, Repeatedly sending an ANQP query request to the server can be a waste.

In the 802.11ai project, the concept of an ANQP configuration sequence number has been developed, which is also known as a common ANQP group version number (CAG version number), and is currently shared by the IEEE 802.11 task group Ai with a common ad group version number (also abbreviated CAG version number) Is associated with a group of access network service features and parameters represented in the form of ANQP elements. This group of ANQP elements is referred to as a common ANQP group (CAG) and has been renamed to a common ad group (CAG) by the current IEEE 802.11 task group Ai. The ANQP server and the vendor of the access network can determine that the ANQP element is in the CAG and can maintain the CAG version number. The CAG version number is incremented each time the member ANQP element in the CAG is changed or any attribute value of the member ANQP element in the CAG is changed. During a previous visit to the AP, the STA may send a CAG (i.e., a group of ANQP elements) associated with the AP, a corresponding CAG version number and range value, a BSSID, a HESSID, and / And / or obtain the ESSID of the AP. This information may be referred to as higher layer information. The STA may store the upper layer information for later use.

The CAG number element is defined in the IEEE Draft 802.11ai Amendment D2.0 so that the AP indicates to the STA the current CAG version number. The AP may obtain the current CAG version number from the corresponding ANQP server. An AP may include a CAG number element within a beacon frame or probe response frame that the AP transmits to the outside. The CAG number element contains the CAG information (upper layer information) stored by the STA for the AP during the previous visit, i.e., the group of ANQP elements and the CAG version number in which the values ​​in these ANQP elements are stored and the CAG version in the received CAG number element May be used by the STA to determine whether it is still currently valid by comparing the numbers. If the two CAG version numbers are the same, the STA can use the stored CAG information to continue the NDS process without initiating the ANQP query process, since the query responses obtained in other ways will be the same as stored. As such, the number of ANQP query requests and responses and the number of associated GAS frames may be reduced.

Figure 8 shows the format of the CAG number element in IEEE Draft 802.11ai Amendment D2.0. 8, the CAG number element 800 includes an element ID field 810 including an element identifier value corresponding to a CAG number element, a length indicating a length of a field remaining in the CAG number element in octets Field 820, a CAG version field 830 indicating the current CAG version number, and a Scope field 840. Since the value in the CAG version field 830 is always positive, a value of 0 in this field will be ignored by the receiving STA. The range field 840 includes a value indicating the valid range of the CAG associated with the value contained in the CAG version field 830. [ A value of 0 in the scope field 840 indicates that the CAG is only valid within the current Basic Service Set (BSS), identified by the BSSID value of the AP. A value of 1 in the scope field 840 indicates that the CAG is valid within the Homogeneous Extended Service Set (ESS) of the AP, identified by the HESSID value. And a value of 2 in the scope field 840 indicates that the CAG is valid within the extended service set (ESS), which is the association of the BSS with the same SSID of the AP. A value of 3 to 255 is currently reserved for the range field 840.

As previously described, including the CAG version (within the CAG version element) within the beacon frame periodically broadcasted by the AP helps to reduce the number of ANQP query requests and query responses. This approach is generally characterized as & quot; push & quot ;. However, inclusion of the CAG number element in the beacon also implies additional signaling overhead that the AP must periodically transmit. Considering that in places where a large number of Wi-Fi STAs frequently visit, such as railway stations and shopping malls, the benefit of reducing frequent ANQP query exchanges can outweigh the price of transmitting additional signaling overhead in beacon frames, It may be worthwhile for the AP to "push" the current CAG version number to the STA by broadcasting the current CAG version number within the beacon frame. However, given that the Wi-Fi STA's density is not high, and most APs do not receive ANQP queries as often as they actually transmit beacon frames, these APs do not include the CAG number IE in their beacon frame Can be selected. Thus, it may be better to use a & quot; pull & quot; mechanism when the STA desiring to know the current CAG version number sends a request for information that should be returned by the responder.

Such a "full" mechanism was provided in Draft 802.11ai Amendment D2.0. Draft 802.11ai Amendment D 2.0 defines a CAG ANQP element, as shown in FIG. 9, the CAG ANQP element 900 includes an information ID (Info ID) field 910 including an identifier value corresponding to a CAG ANQP element, a total length of a field remaining in the CAG ANQP element 900 A CAG version field 930 containing the current CAG version number associated with the CAG, and an information ID field 940, including the identifier of the member ANQP element in the CAG, (CAG member), such as an & lt; RTI ID = 0.0 & gt; ID field 950. & lt; / RTI & gt; The number of information IDs (CAG members) included in the CAG ANQP element 900 is the number of CAG members (such as the information ID field 940 and the information field 950) Since the length of the information ID field is fixed, it can be deduced from the value contained in the length field 920. [ Such a CAG ANQP element may be pooled (meaning requested) by the STA by using the query list ANQP element in the ANQP query request encapsulated in the GAS initial request frame. An alternative "full" mechanism involves waiting for a probe response after the STA sends a probe request frame requesting the CAG number IE to be returned. The difference between these two alternative approaches, While the probe request is responding by an AP that can provide the current CAG version number in response but can not provide the contents of the CAG, the ANQP query request may be an additional ANQP element that may ultimately be an external CAG, And is answered by the ANQP server which can additionally provide the contents of the CAG. One of these two & quot; full & quot; mechanisms may result in an additional delay to determine the NDS due to waiting for a response.

STA vendors tend to focus on optimizing STA designs for a better user experience than for network capacity. Sometimes, in practice, shortening the network discovery and selection (NDS) delay means having a higher priority than reducing the signaling overhead associated with the STA. If the AP does not broadcast the CAG number IE in the beacon frame, the STA implementation may ignore the CAG information that could all be stored together by initiating the ANQP query to obtain the most recent CAG information directly from the server, You can make a very good choice to avoid query delays.

10 illustrates a message exchange flow diagram 1000 highlighting exemplary message exchanges during a network discovery process occurring among STA, AP, and ANQP servers when the AP does not include a CAG number IE in the beacon periodically broadcasted . 10, the message exchange flow diagram 1000 includes operations performed by STA 1005, AP 1010, and / or ANQP server 1015, as well as operations performed by STA 1005, AP 1010, and / , And ANQP server 1015, respectively. The message exchange flow diagram 1000 may begin with the step of the STA 1005 obtaining the CAG version number associated with the CAG from the ANQP server 1015 while visiting the AP 1010 (illustrated as event 1020). STA 1005 may store CAG information (i.e., upper layer information), CAG version number, and AP information for later use. Then, at the next time, STA 1005 revisits AP 1010 and receives a beacon frame from AP 1010 (illustrated as event 1025).

Because of the concern of signaling overhead as previously described, the AP 1010 does not include the CAG number IE in the beacon frame. From the BSSID, which is typically the MAC address of the AP, contained within the beacon, the STA 1005 may be aware to store the CAG information associated with the AP 1010. However, since the AP 1010 does not include the CAG number IE in the beacon frame, the STA 1005 does not know that the CAG information stored in association with the AP remains valid. To prevent probing or query delays, STA 1005 chooses to ignore the stored CAG information and sends a GAS initial request frame (illustrated as event 1030) to encapsulate the ANQP query request. After receiving the GAS initial request frame, the AP 1010 sends an advertisement protocol ID within the advertisement protocol element (such as advertisement protocol element 320) and a query request (such as a query request field 360) And a protocol that should be used to carry a query request between the AP 1010 and the ANQP server 1015 based on the initial connection established between the AP 1010 and the ANQP server 1015 from the advertising protocol ID The ANQP server 1015 is selected (as exemplified by event 1035) to forward the query request as well as the frame and transmission means. Diameter and RADIUS belong to example protocols commonly used between APs and servers.

The AP 1010 then forwards the ANQP query request to the ANQP server 1015 using the selected protocol frame and transmission means (illustrated as event 1040). After receiving the protocol frame from the AP 1010, the ANQP server 1015 retrieves the ANQP query request and generates an ANQP query response accordingly (illustrated as event 1045). The ANQP server 1015 then sends an ANQP query response to the AP 1010 using another protocol frame (illustrated as event 1050). After receiving the response protocol frame from the ANQP server 1015, the AP 1010 retrieves the ANQP query response and encapsulates the ANQP query response in the query response field (such as query response field 760) within the GAS initial response frame And transmits it to the STA 1005 using the GAS initial response frame (illustrated as event 1055).

As shown in FIG. 10, STA 1005 is looking for a quick way to ensure that it has information on the access network to perform network selection decisions. Because the AP 1010 does not include the CAG number IE in the beacon frame, the STA 1005 does not use the stored CAG information, because it may cause additional delay to "pool" the current CAG version number first I choose not to. In practice, a large number of STAs can certainly adopt the same strategy and, therefore, can be less useful than that by providing CAG features, as defined in draft 802.11ai Amendment D2.0.

In order to overcome the above disadvantages, an improved signaling mechanism is provided in the exemplary embodiment shown here. According to the illustrative embodiment, the STA provides the AP with the CAG version number associated with the AP stored by the STA during initiating the GAS query request, which means that the STA provides the CAG version number stored in the GAS initial request frame. The AP then compares the CAG version number stored by the STA with the most recent CAG version number received from the ANQP server. If the two CAG version numbers are the same, the AP keeps the stored CAG version number (and hence the stored CAG information associated therewith) the same as the current one, the CAG information stored when the requesting STA makes a network selection decision And therefore shortens the query process by returning a GAS initial response frame that conveys to the requesting STA an indication that the ANQP query process is terminated. If the two CAG version numbers are different, the AP delivers the query request to the ANQP server as usual and the remaining steps in the conventional ANQP query process are performed.

The design challenge for carrying the CAG version number stored by the STA in the GAS initial request frame is that it should not be carried within the ANQP element encapsulated in the query request field, since the AP does not need to understand the contents of the query request. Likewise, another design challenge for carrying the indication that the stored CAG version number is the same as the current one in the GAS initial response frame is that the indication should not be carried within the encapsulated ANQP element in the query response field. In the illustrative embodiment, even though the AP may build the ANQP element and include it in the query response field to indicate that the stored CAG version number is the same as the current one, doing so would destroy the traditional protocol layering structure And to add additional functional requirements for it. In addition, in the case of an advertisement protocol in which a query request and a query response can be defended by end-to-end encryption between the requesting STA and the server, an intermediate AP may not be able to successfully establish a query response. Thus, such an embodiment may not be realistic. On the other hand, since adding a new field may not be an option, the field carried in the GAS initial request frame, not the query request field, and the field carried in the GAS initial response frame other than the query response field are fixed for reasons of compatibility.

According to the illustrative embodiment, the additional signaling needed is provided by reusing existing fields in the GAS initial request and GAS initial response frames in a backwards compatible manner.

In an exemplary embodiment, if the ad protocol element is included in the GAS initial request frame, the query response information field in the ad protocol element may be used to include the CAG version number stored by the STA. FIG. 11 shows the format of the example advertisement protocol element 1100 when the advertisement protocol element is included in the GAS initial request frame. The advertisement protocol element 1100 is improved and modified, for example, from the advertisement protocol element 320. 11, the enhanced advertisement protocol element 1100 includes an IE ID field 1110 containing the same element identifier value that the advertisement protocol element currently contains, the length of the field remaining in the element in the octet A query response information-CAG version field 1130, and an advertisement protocol ID field 1140. The length field 1120 indicates the length of the query response information. The definition and value of the advertising protocol ID field 1140 is the same as the current value of the advertising protocol ID field (such as the advertising protocol ID field 331). When included in the GAS initial request frame, if the STA stores the CAG (i.e., upper layer information) and the associated CAG version number corresponding to the AP and the advertising protocol being used, the query response information- Includes the CAG version number stored therein; Alternatively, the STA is set to a value of zero if the STA does not have a stored CAG, or an associated CAG version number corresponding to the AP or the advertising protocol being used. This is consistent with the concept of Draft 802.11ai D2.0, where 0 is not a valid CAG version number. The CAG version number is also associated with the advertising protocol being used. Thus, the CAG version number included in the query response information-CAG version field 1130 is associated with the advertising protocol indicated by the value contained in the advertising protocol ID field 1140. [ The query response information-CAG version field 1130 includes a 7-bit query response limit sub-field (such as a query response length limit sub-field 327) when included in the beacon, probe response, GAS initial response, or GAS return response frame And a 1-bit PAME-BI subfield (such as PAME-BI subfield 329).

In an alternative exemplary embodiment, instead of modifying an existing query response information field (such as the query response information field 325), the requesting STA may send a request to the AP in the GAS initial request frame CAG number IE. However, this CAG number ID will be inserted into the GAS initial request frame after the query request field (such as query request field 360) to maintain backward compatibility, and since the AP does not need to interpret the content in the query request field , Meaning that the value in the query request length field will not count the CAG number IE as part of the query request field).

In another exemplary embodiment, the new status code value contained within the status code field (such as status code field 720) in the GAS initial response frame indicates that the current CAG version number remains the same as the CAG version number stored by the STA It is used to instruct the requesting STA. Such a new status code value also serves to instruct the requesting STA that the stored CAG information is still valid for making such a decision as the network selection decision and thus the query process initiated by the STA is terminated.

12 illustrates a message exchange flow diagram 1200 highlighting exemplary message exchange during network discovery, service discovery, or information discovery that occurs between the STA, the AP, and the server, where the STAs and APs may be enhanced Signaling mechanism. 12, the message exchange flow diagram 1200 may include operations performed by the STA 1205, the AP 1210, and / or the STA 1205, as well as the work performed by the STA 1205, the AP 1210, and / Lt; / RTI & gt; and server 1215, respectively. The advertisement protocol used between the STA 1205 and the server 1215 may be ANQP or a pre-association discovery protocol (PADP) that is not yet defined by the RLQP or 802.11aq project, Or any other advertising protocol such as any other yet undefined ad protocol that may use any public action frame to be defined as a transport. Accordingly, the server 1215 may be an ANQP server, an RLQP server, a PADP proxy or a server, or a server supporting a plurality of these protocols.

The message exchange flow diagram 1200 may begin with the STA 1205 obtaining the CAG version number and associated CAG version number from the server 1215 during the visit to the AP 1210 Lt; / RTI & gt; The STA 1205 may store CAG information, CAG version number, range values, and AP / server information (such as the identifier of the AP, the advertising protocol used by the server) for future use. Meanwhile, the AP 1210 may obtain an update of the most recent CAG version number from the server 1215 (illustrated as event 1225) if a change occurs periodically or in a CAG version number. At a subsequent time thereafter, the STA 1205 may revisit the AP 1210 and receive a beacon frame from the AP 1210 (illustrated as event 1230). Because of concern with the signaling overhead as previously described, the AP 1210 can not include the CAG number IE in the beacon frame. From the BSSID contained in the beacon frame, the STA 1205 may recognize that it has stored the CAG information and the CAG version number associated with the AP 1210. STA 1205 may send a GAS initial request frame to AP 1210 (illustrated as event 1235). The GAS initial request frame is associated with the AP 1210 and may be used in the query response information-CAGqjwjs field (e.g., in the query response information-CAG version field 1130) 1130) (as indicated by the values ​​contained in the CAG version number 1130).

After receiving the GAS initial request frame from the STA 1205, the AP 1210 transmits the CAG number stored by the STA and the CAG number stored in the GAS initial request frame received from the server 1215, for example, (As illustrated by event 1240) the latest CAG version number (e.g., associated with the same advertising protocol as indicated by the value contained in the advertising protocol ID field 1130 in FIG. If the AP 1210 determines that the two CAG version numbers are the same, the AP 1210 may send a GAS initial response frame to the STA 1205, and the GAS initial response frame may include (e.g., (Such as a network selection decision, a service selection decision, a peer device selection decision, etc.) in the status code field (e.g., the number 720), the stored CAG version number is the same as the current CAG version number that the AP has , And may include a status code value indicating that the query request initiated by the requesting STA is eventually terminated (illustrated as event 1245). The GAS initial response frame transmitted by AP 1210 at event 1245 does not include a query response field. A value of 0 included in the query response length field (such as query response length field 750) indicates that the query response field is not included in the GAS initial response frame. After receiving the GAS initial response frame, the STA 1205 may terminate the query process.

If the AP 1210 determines that the two CAG version numbers are not the same at event 1240, the AP 1210 sends an entry in the GAS initial request field within the query request field (e.g., in the query request field 360) You can search for embedded query requests. From the advertising protocol IDs contained in the advertising protocol ID field 1130, the AP 1210 can send a query request between the AP 1210 and the server 1215, as well as the protocol frame and transmission means that should be used to carry the query request, Lt; RTI ID = 0.0 & gt; 1215 & lt; / RTI & gt; The AP 1210 may then communicate the query request to the server 1215 using the selected protocol frame and transmission means (illustrated as event 1250). After receiving the protocol frame from AP 1210, server 1215 retrieves the query request from the protocol frame and generates a corresponding query response (illustrated as event 1255). The server 1215 then sends a query response to the AP 1210 using a different protocol frame (illustrated as event 1260)

After receiving the response protocol frame from the server 1215, the AP 1210 retrieves the query response, and if the query response is not large, the AP 1210 resets the GAS initial response frame (e.g., query response field 760) Encapsulates the query response within the query response field, and passes it to the STA 1205 using the GAS initial response frame. The query process can then be terminated. If the query response is large, the AP 1210 breaks down the query response into a plurality of GAS return response frames, invites the requesting STA to request to receive a plurality of GAS return response frames to retrieve the entire query response And sends the initial GAS response frame. The STA 1205 then transmits the GAS Return Request frame, correspondingly receives the GAS Return Response frame, and repeats these steps until a GAS Return Response frame carrying the last segment of the query response is received. The STA 1215 may then reassemble the query response. The query process can then be terminated.

As shown in FIG. 12, if the CAG version number stored by the STA is the same as the current one, the STA 1205 may be configured to allow the STA 1205 to make a decision (e.g., for network selection) faster for a better user experience (As illustrated in event 1245), it is motivated to provide the stored CAG version number. Although the stored CAG version number of the STA is different from the current one, the AP 1210 still faithfully delivers the query response to the server 1215. [ The STA 1205 immediately obtains a recent query response from the server 1215. Thus, by using an improved signaling mechanism as shown in the exemplary embodiment shown here, more STAs will be motivated to use the CAG information they have.

The GAS initial response frame sent in event 1245 does not include a query response field. Compared to using the probe request and probe response frame to obtain the current CAG version number as described previously, in terms of signaling overhead, the GAS initial request frame is used to supply the stored CAG version number , It is a very efficient alternative to receive a GAS initial request frame with an indication of whether the stored CAG version number is equal to the current one. However, some modification must be made on the GAS initial request frame. As defined in the current IEEE Standard 802.11-2012 and draft 802.11ai Amendment D 2.0, the GAS initial request frame will contain a query request field in which the query request of the advertisement protocol is encapsulated. Thus, a value of 0 in the query request length field in the GAS initial request frame is no longer allowed.

According to an alternative exemplary embodiment of an improved signaling mechanism, the GAS initial request frame without query request field and the GAS initial response frame without query response field are used for using probe request and probe response frame to pool the CAG version number do. Strictly speaking, it is not a "pull" mechanism, as the requesting STA does not obtain the current CAG version number. Instead, it simply states whether the STA supplies its stored CAG version number to the AP using the GAS seconds request frame and the AP provides an indication in response to whether the stored CAG version number is the same as the current one To obtain instructions for.

Figure 13 shows a message exchange flow diagram 1300 that highlights an alternative exemplary message exchange during a network discovery, service discovery, or information discovery process that occurs between the STA, the AP, and the server, where the STA and the AP provide enhanced signaling Mechanism and the STA is also optimized to efficiently use the signaling overhead to conserve network capacity. 13, the message exchange flow diagram 1300 includes information about the operations performed by STA 1305, AP 1310, and / or STA 1305, as well as operations performed by STA 1305, AP 1310, and / Server 1315. In the example of FIG. The message exchange flow diagram 1300 may begin with the STA 1305 acquiring the CAG version number associated with the CAG from the server 1315 during a visit to the AP 1310 (illustrated as event 1320). STA 1305 may store CAG information, CAG version number, range value, and AP / server information for later use. Meanwhile, the AP 1310 may obtain an update of the latest CAG version number from the server 1315 (illustrated as event 1325), if the change occurs periodically or on the CAG version number.

STA 1305 may then revisit AP 1310 and receive a beacon frame from AP 1310 (illustrated by event 1330). Because of the concern of signaling overhead as described previously, AP 1310 can not include the CAG number IE in the beacon frame. From the BSSID contained in the beacon frame, the STA 1305 may recognize that it has stored the CAG information and the CAG version number associated with the AP 1310. STA 1305 then sends AP 1310 a query response information-CAG version field (such as query response information-CAG version field 1130) associated with the AP and containing its stored CAG version number (As indicated by the value contained in the advertising protocol ID field 1130), which does not include the query request field within the GAS initial request frame (as exemplified by event 1335) ). A value of 0 included in the query request length field (such as the query request length field 340) indicates that the query request field is not included and that the GAS initial request frame contains the STA's stored CAG version number that the AP 1310 has Is sent to request an indication of whether the current CAG version number is equal to the current CAG version number.

After receiving the GAS initial frame from the STA 1305, the AP 1310 sends the stored CAG version number of the STA and, for example, the AP 1310 received from the server 1315 It may compare the latest CAG version number (e.g., of the same advertising protocol indicated by the value contained in the advertising protocol ID field 1130 in the request frame). Thereafter, according to the comparison result, the AP 1310 transmits a GAS initial response frame to the STA 1305 (illustrated as an event 1345). If the AP 1310 determines that the two CAG version numbers are the same, then the AP 1310 sends the CAG version number stored therein (e.g., in the status code field 720) Lt; RTI ID = 0.0 & gt; a & lt; / RTI & gt; current CAG version number. If the AP 1310 determines that the two CAG version numbers are not the same, then the AP 1310 determines whether the CAG version number stored in the status code field (such as the status code field 720) Lt; RTI ID = 0.0 & gt; CAG & lt; / RTI & gt;

After receiving the GAS initial response frame from the AP 1310, if the first status code value is included in the status code field, the STA 1305 may terminate the query process. STA 1205 may continue to make a decision or may initiate a query process to another AP and / or another server before making a decision on how to proceed with the network selection process. If the second status code value is included in the status code field, the STA 1305 knows that its stored CAG information is obsolete. Thus, the STA 1305 may initiate a normal query request to obtain the latest CAG information (illustrated as event 1350). And the remaining events of the normal query process, such as events 1355, 1360, 1365, 1370 and 1375. As shown in FIG. 13, when compared to STA 1205 as shown in FIG. 12, at event 1335 (due to an extended query request from the GAS initial request frame), some signaling Overhead, but has the risk of introducing a longer delay (when compared to STA 1205) if the two CAG version numbers are different.

In the current 802.11-2012 and draft 802.11ai Amendment D2.0 in the IEEE standard, if the advertisement protocol element is included in the GAS initial request frame, the query response information field is set to 0 and the AP receiving this query information field I will ignore it. Thus, a legacy AP that receives a GAS initial request frame at event 1235 (e.g., can use CAG frames but can not use CAG features or signaling enhancements) will forward a query request to the server based on legacy 802.11u rules . The stored CAG version number provided by the STA may be exhausted, but the 802.11u query process still remains intact. In fact, if the requesting STA knows from the capabilities indicated in the beacon or probe response, for example, that the AP is a legacy AP, then the STA sets its query response information-CAG version field to 0, It is possible to prevent transmission of the stored CAG version number. This is consistent with the draft 802.11ai Amendment D2.0, where 0 is not a valid CAG version number. Instead, a value of 0 in the query response information-CAG version field soo in the initial GAS request will support an enhanced signaling mechanism to indicate that the STA has a stored CAG version number for the AP and no associated advertising protocol , May be used by the STA (and may be interpreted by the AP supporting the improved signaling mechanism). The GAS initial request frame is transmitted (e.g., An AP that supports the improved signaling mechanism, because the legacy STA sets the query response information field to 0, although it can use the GAS frame but can not use CAG features or signaling enhancements, , It will treat it as if it does not have an associated advertising protocol. Therefore, the AP will not shorten the query process. Thus, in summary, the illustrative embodiments shown herein do not have backward compatibility issues with legacy APs or legacy STAs. The communication system made in these illustrative embodiments can coexist with the legacy AP and the legacy STA.

14A shows a flow diagram of a first example task 1400 that occurs at an STA participating in a network discovery, service discovery, or information discovery process. Task 1400 may indicate an operation occurring at the STA as the STA participates in network discovery, service discovery, or information discovery. Task 1400 may correspond to message exchange flow diagram 1200.

Task 1400 may begin with the STA obtaining the first higher layer information and the CAG number from the server (block 1405). The first higher layer information and the CAG number may be related to a network, a service, a database, and the like. The STA may be detached from the network (block 1407). At a later time, the STA may revisit the network (block 1409), which may be verified, for example, according to the BSSID contained in the beacon frame transmitted by the AP. The STA may send a GAS initial request frame containing the stored CAG version number (block 1411). The STA may receive a GAS initial response frame with an indicator indicating whether the stored CAG version number matches the current CAG version number (block 1413). The indicator may be located in the status code field of the GAS initial response frame. If the stored CAG version number matches the current CAG version number, the GAS initial response frame does not contain any upper layer information. If the stored CAG version number does not match the current CAG version number, the GAS initial response frame received by the STA may include the upper layer information and the current CAG number in the query response field. The STA may continue the network selection process (block 1415).

14B shows a flowchart of a second exemplary operation 1450 that occurs in the STA participating in the network discovery, service discovery, or information discovery process. Task 1450 may indicate an operation occurring in the STA as the STA participates in network discovery, service discovery, or information discovery. Task 1450 may correspond to message exchange flow diagram 1300.

Task 1450 may begin with the STA obtaining the first higher layer information and the CAG number from the server (block 1455). The first higher layer information and the CAG number may be related to a network, a service, a database, and the like. The STA may be detached from the network (block 1457). At a later time, the STA may revisit the network, which may be verified, for example, according to the BSSID contained in the beacon frame transmitted by the AP (block 1459). The STA may send a GAS initial request frame containing the stored CAG version number (block 1461). The STA may receive a GAS initial response frame with an indication that the stored CAG version number is equal to the current CAG version number (block 1463). The indicator may be located in the status code field of the GAS initial response frame. If the stored CAG version number matches the current CAG version number, the first indicator value is included in the GAS initial response frame, e.g. contained in the status code field; Otherwise, the second indicator value is included in the GAS initial response frame, e.g., contained in the status code field.

The STA may perform a check on the indicator (e.g., the value contained in the status code field) within the received GAS initial response frame to determine if the first indicator value is received (block 1465). If a first indicator value is received (e.g., in the status code field) indicating that the stored CAG version number matches the current CAG version number, the STA may continue the network selection process (block 1469). If the first indicator value indicating that the stored CAG version number does not match the current CAG version number is received, the STA obtains the current upper layer information (updated CAG information) and the current CAG version number from the AP (Block 1467). As shown in the example, the STA can perform normal query requests to obtain updated upper layer information (updated CAG information) and the current CAG version number from the AP. The STA may continue the network selection process (block 1469).

15A shows a flow diagram of a first example task 1500 occurring at an AP participating in network discovery, service discovery, or information discovery. Task 1500 may indicate an operation occurring at the AP as the AP participates in network discovery, service discovery, or information discovery. Task 1500 may correspond to message exchange flow diagram 1200.

Operation 1500 may begin with the AP receiving a GAS initial request frame containing the stored CAG version number stored in the STA (block 1505). The AP may perform a check to determine whether the stored CAG version number from the GAS initial request frame matches the current CAG version number associated with the same advertising protocol (block 1507). If the two CAG version numbers match, the AP may send to the GAS initial response frame with an indication that the two CAG version numbers match (block 1509). If the two CAG version numbers do not match, the AP retrieves the query request from the GAS initial request frame and passes the query request to the server to get a response (block 1511). The AP may receive a response from the server (block 1513). The response from the server may include a query response for the requesting STA. The contents of the query response may include the latest CAG version number and upper layer information that may be transparent to the AP. The AP may retrieve the query response from the response received from the server and send the GAS initial response frame with the query response (block 1515).

15B shows a flowchart of a second example operation 1550 that occurs at an AP participating in network discovery, service discovery, or information discovery. Task 1550 may indicate an action occurring at the AP as the AP participates in network discovery, service discovery, or information discovery. Task 1550 may correspond to message exchange flow diagram 1300.

Operation 1550 may begin with the AP receiving a first GAS initial request frame containing the stored CAG version number stored in the STA (block 1555). The first GAS initial request frame may not include the query request. For example, the query request length field contains a value of 0, and the query request field is null. A check may be performed to determine if the stored CAG version number from the GAS initial request frame matches the current CAG version number associated with the same ad protocol (block 1557). If the two CAG version numbers match, the AP may send a first GAS initial response frame with an indication that the two CAG version numbers match.

If the two CAG version numbers do not match, the AP may send a first GAS initial response frame with an indication that the two CAG version numbers do not match (block 1561). The AP may receive a second GAS initial request frame containing the query request (block 1563). The content of the query request, which may be transparent to the AP, may include a request for a recent CAG version number and higher layer information (CAG information). The AP may retrieve the query request from the second GAS initial request frame and forward the query request to the server for a response (block 1565). The AP may receive a response from the server (block 1567). The response from the server may include a query response for the requesting STA. The content of the query response, which may be transparent to the AP, may include the latest CAG version number and upper layer information (CAG information). The AP may retrieve the query response from the response received from the server and send a second GAS initial response frame with the query response (block 1569).

The CAG number is also associated with the advertising protocol in use. Thus, if the AP advertises the current CAG version number using the CAG number IE included in the beacon or probe response frame, the AP MUST also indicate the ad protocol associated with that CAG version number. Figure 16 shows an example CAG number IE 1600 including the ID of the advertising protocol associated with the CAG version number. 16, the CAG number IE 1600 includes an IE ID field 1610 containing an element identifier value corresponding to the CAG number element, a length indicating the total length of the field remaining in the element, in octets, One or more CAG tuple fields, such as a field 1620, a CAG tuple field 1630, a CAG tuple field 1650, and a CAG tuple field 1660. Each CAG tuple field (such as CAG tuple field 1630) includes a CAG version subfield of one octet (such as CAG version subfield 1635), a range subfield of one octet (such as range subfield 1640) , And an advertisement protocol ID subfield of one octet (such as advertisement protocol ID subfield 1645). The number of CAG tuple fields contained within the CAG number element 1600 may be deduced from the values ​​contained in the length field 1620.

FIG. 17 shows an example Alternative Embodiment CAG number ID 1700. FIG. As shown in FIG. 17, the CAG number IE 1700 includes an IE ID 1710 containing an element identifier value corresponding to the CAG number element, a length field indicating the total length of the field remaining in the element, One or more CAG tuple fields such as a CAG tuple field 1720, a CAG tuple field 1730, a CAG tuple field 1750, and a CAG tuple field 1760. Each CAG tuple field (such as CAG tuple field 1730) includes a one octet CAG version subfield (such as CAG version subfield 1735), a 3-bit range subfield (such as range subfield 1740) ), And a 5-bit partial advertisement protocol ID subfield (such as partial advertisement protocol ID subfield 1745). The number of CAG tuple fields contained within the CAG number element 1700 may be deduced from the values ​​contained in the length field 1720. The CAG number IE 1700 is replaced with a 5-bit partial advertisement protocol ID subfield 1745 (the advertisement protocol ID subfield 1645) 1640) is replaced with a 3-bit range sub-field 1740, which is different from the CAG number IE 1600 in that these two sub-fields are combined into one octet . Thus, each CAG x tuple field in the CAG number IE 1700 has a length of two octets instead of three octets as in the CAG number IE 1600. The 5-bit partial advertising protocol ID may be the first 5 bits (i.e., the 5 least significant bits) of the advertising protocol ID of one octet, as currently defined, which allows overlapping among the partial advertising protocol IDs , Only a total of 32 one-octet advertisement protocol IDs can be allocated. If the CAG version number contained in the CAG version subfield (such as CAG version subfield 1735) is associated with ANQP, as in the depicted example, then the entire advertisement protocol ID for ANQP is 0 (or represented as a binary number 0.0 & gt; 00000000), & lt; / RTI & gt; the partial advertisement protocol ID subfield in the same CAG tuple field (such as partial advertisement protocol ID subfield 1745)

[Table 1] provides a full advertising protocol ID value and a partial advertising protocol ID value to which they are associated, which are represented by a number of example advertisement protocols and all in decimal, and which can be applied to the example formats shown in Figures 16 and 17, respectively .

<tables num="1"><table><tgroup cols="3"><colspec colnum="1" align="center" colname="col1" colwidth="3600" /><colspec colnum="2" align="center" colname="col2" colwidth="3600" /><colspec colnum="3" align="center" colname="col3" colwidth="3600" /><tbody><row><entry align="center" colname="col1">Ad protocol name</entry><entry align="center" colname="col2">Ad Protocol ID Value</entry><entry align="center" colname="col3">Partial advertising protocol ID value</entry></row><row><entry align="center" colname="col1">Access Network Query Protocol (ANQP)</entry><entry align="center" colname="col2">0</entry><entry align="center" colname="col3">0</entry></row><row><entry align="center" colname="col1">MIH Information Service</entry><entry align="center" colname="col2">One</entry><entry align="center" colname="col3">One</entry></row><row><entry align="center" colname="col1">Discovery of MIH Command and Event Service Capabilities</entry><entry align="center" colname="col2">2</entry><entry align="center" colname="col3">2</entry></row><row><entry align="center" colname="col1">Emergency alarm system (EAS)</entry><entry align="center" colname="col2">3</entry><entry align="center" colname="col3">3</entry></row><row><entry align="center" colname="col1">Registered Location Query Protocol (RLQP)</entry><entry align="center" colname="col2">4</entry><entry align="center" colname="col3">4</entry></row><row><entry align="center" colname="col1">The Dictionary Association Discovery Protocol (PADP)</entry><entry align="center" colname="col2">5</entry><entry align="center" colname="col3">5</entry></row><row><entry align="center" colname="col1">Hold</entry><entry align="center" colname="col2">6-220</entry><entry align="center" colname="col3">6-26</entry></row><row><entry align="center" colname="col1">Vendor specification</entry><entry align="center" colname="col2">221</entry><entry align="center" colname="col3">27</entry></row><row><entry align="center" colname="col1">Hold</entry><entry align="center" colname="col2">222-255</entry><entry align="center" colname="col3">28-31</entry></row></tbody></tgroup></table></tables>

The number of range values ​​that can be defined by a 3-bit range subfield (such as range subfield 1740) may also be reduced by a range subfield of length 1 octet (such as range subfield 1640) to 256 , It is reduced to 8. Since the number of range values ​​of the 3-bit range sub-field is significantly reduced, one possible solution is to provide a 3-bit sub-field within the 3-bit range sub-field based on the corresponding partial advertisement protocol ID value contained in the same CAG tuple field It is to reinterpret the meaning of each range value. If, as in the illustrated example, the partial advertisement protocol ID indicates that the associated advertisement protocol is ANQP, a value of 0 in the 3-bit range subfield may indicate that the CAG number is specific to the BSS, May indicate that the CAG number is common within the same HESSID, and a value of &amp; quot; 2 &amp; quot; may indicate that the CAG number is common within the same extended service set (ESS) A value of 3 to 7 may be reserved as a range subfield for ANQP; On the other hand, if the Partial Advertising Protocol ID indicates that the associated advertising protocol is RLPQ (for TV White Space technology), then 0, 1, 2, 3, 4, A value of 5 indicates that the CAG number associated with the TV white space database or the map of channel availability is common across the country, across the state, across the county, in transit, across the ESS, or throughout the BSS &amp; Lt; / RTI &amp; gt;

18 shows a flow diagram of an example task 1800 that occurs in a communication device transmitting a frame containing a CAG number IE. Task 1800 represents a task occurring on a communication device as a communication device, such as an STA and / or an AP, transmits a frame containing a CAG number IE.

Operation 1800 may begin with the communication device generating a frame containing the CAG number IE according to FIG. 16 or 17 (block 1805). The frame may be a beacon frame, a probe response frame, a GAS initial request frame, a short beacon frame, a public action frame, or the like. The CAG number IE may include one or more CAG tuples, each CAG tuple comprising a CAG version field, a range field (which may be either 3 bits in length or 8 bits in length) Lt; RTI ID = 0.0 &amp; gt; ID &amp; lt; / RTI &amp; gt; The communication device may transmit the frame (block 1810).

The GAS initial request and the GAS initial response frame are used only as an example to illustrate the exemplary embodiment. Any other public action frame such as a service discovery request frame and a service discovery response frame defined in the WFA Wi-Fi Direct specification, or any other public action frame such as an upper layer query request and a layer 2 transmission of query response data. A new public action frame is also possible.

The illustrated exemplary embodiment described is not only for enhancing the current 802.11ai CAG feature as defined in Draft 802.11ai Amendment D2.0 defined for ANQP only, , Media independent handover (MIH) information service, media independent handover (MIH) command and event service capability discovery (MIH command), as well as an undefined advertisement protocol such as PADP, such as RLQP, as defined in the 802.11af fix for access control, discovery and event services capability discovery, emergency alert system (EAS), access network discovery and selection function (ANDSF) Can be applied to enhancing the advertising protocol. Accordingly, the server may be a server supporting one or more of ANQP, MIH, RLQP, PADP, and ANDSF. The CAG may be defined as any group of upper layer information associated with an upper layer protocol using layer 2 frames as a means of transport between the STA and the AP to which the server is connected. For example, the higher layer information may be associated with a database of service information, protocol information, configuration information, TV white space map, or channel availability information. The use of such techniques may be a kind of discovery purpose. For example, the discovery process may be network discovery, and the network may be an access network, A subscription service provider network (SSPN), and / or a cellular network, service discovery, information discovery or available TV white space channels. The decision to be made after the discovery process may be any kind of decision such as network selection decisions, service selection decisions, peer device selection decisions, decisions to use TV white space channels available for communication, and so on. The CAG version number may also be referred to as a configuration change count, a configuration sequence number, a configuration set number, a TV white space map index number, and the like.

In general, a station (or device, user device, terminal, mobile, etc.) uses Layer 2 transmission between the station and the access point and also between the access point and the server, (Or base station, controller, Nobe B, enhance Node B, etc.). The index number (or version number, change count, configuration sequence number, etc.) may be associated with higher layer information. The index number and higher layer information may be provided to the station from the server and stored by the station, for example, during a previous visit. A recent index number may also be provided to the access point by the server. At a subsequent visit to the access point by the station, the station may provide its stored index number to the access point. Because the higher layer information may be associated with a higher layer protocol identified by the protocol identifier, the station may also provide the associated protocol identifier to the access point. The access point can compare the index number provided by the station with the index number provided by the server. The access point may use the protocol identifier provided by the station to select the server of the index number compared to the index number provided by the station. If the two index numbers are the same, then the access point may not be able to receive higher layer information from the server, such as for selecting a network, discovering a service, etc., So that the station can be instructed to use the stored higher layer information.

19 is a block diagram of a processing system 1900 used to implement the apparatus and methods disclosed herein. A particular device may use all of the illustrated components, or only some of the components, and the level of integration may vary from device to device. In addition, an apparatus may include a plurality of component instances, such as a plurality of processing units, a processor, a memory, a transmitter, a receiver, and the like. The processing system includes a processing unit 1905 with one or more input / output devices, such as a human interface 1915 (including a speaker, microphone, mouse, touch screen, keypad, keyboard, . &amp; Lt; / RTI &amp; gt; The processing unit may include a central processing unit (CPU) 1920 connected to a bus 1945, a memory 1925, a mass storage 1930, a video adapter 1935, and an I / O interface 1940 .

The bus may be one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a video bus, and the like. The CPU may include any kind of electronic data processor. The memory may include any kind of system memory, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), ROM, In an embodiment, the memory may include a ROM for use at boot time, and a program for use during execution of the program and a DRAM for data storage.

The mass storage device may include any type of storage device configured to store data, programs and other information, and to generate data, programs, and other information accessed via the bus. The mass storage device may include, for example, one or more solid state drives, hard disk drives, magnetic disk drives, optical disk drives, and the like.

The video adapter and I / O interface provide an interface for combining external input and output devices to the processing device. As shown, examples of input and output devices may include a display coupled to the video adapter and a mouse / keyboard / primer coupled to the I / O interface. Other devices may be coupled to the processing unit and additional or fewer interface cards may be used. For example, a serial interface such as a Universal Serial Bus (USB) may be used to provide an interface to the printer.

The processing unit also includes one or more network interfaces 1950, which may include a wired link, such as an Ethernet cable, and / or a wireless link to access a node or a different network 1955. The network interface allows the processing unit to communicate with the remote unit via the network. For example, a network interface may provide wireless communication via one or more transmitter / transmit antennas and one or more receiver / receive antennas. In an embodiment, the processing unit is coupled to a local-area network or a wide-area network for data processing and communication with remote devices such as other processing units, the Internet, remote storage facilities, and the like.

Although the present disclosure and its advantages have been described in detail, various changes, substitutions and alterations can be made without departing from the scope of the present disclosure as defined by the appended claims.