# US 2015/0146709 A1 · Method and apparatus for acquiring available channel information in a wireless local area network system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0146709 A1 - Document ID: US20150146709A1 - Status: Published application - Kind: A1 - Application number: 14/570,702 - Filed: 2014-12-15 - Published: 2015-05-28 - Earliest claimed: 2010-03-19 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Eun Sun KIM; Yong Ho SEOK - Web page: https://patentgrep.com/patent/US20150146709A1 ## CPC - H04W 74/002: {Transmission of channel access control information} - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W 48/16: Discovering, processing access restriction or access information - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Methods and apparatuses for acquiring/providing available channel information using Generic Advertisement Service (GAS) protocol in a wireless local area network (WLAN) are disclosed. AP (Access Point) station has a capability to acquire information for available channels from a database using a specific protocol related to an operation within the White Space (e.g. Access Network Query Protocol (ANQP)). And, non-AP station can retrieve the information for available channels by transmitting a Generic Advertisement Service (GAS) initial request frame to the AP station, wherein the GAS initial request frame comprises an Advertisement Protocol Element whose element ID indicates the specific protocol, and receiving a GAS initial response frame comprising a White Space Map (WSM) the specific protocol. The WSM comprises one or more white space channel units, and each of the white space channel units comprises a channel number field indicating one of the available channels and a power constraint field indicating a maximum allowable power on the indicated channel. ## Claims ### Claim at position 1 1-18. (canceled) ### Claim 20 A method for performing procedures for interworking with external networks in a wireless local area network (WLAN), the method comprising: transmitting, by a first station to a second station, an advertisement protocol element indicating support for a specific generic advertisement service (GAS) protocol; receiving, by the first station from the second station, a channel availability query (CAQ) request including a GAS protocol element; accessing, by the first station, a database to obtain information on available frequencies; and transmitting, by the first station to the second station, a CAQ response including channel availability information. ### Claim 21 (depends on 20) The method of claim 20, wherein the GAS protocol element is used by the first station and the second station, before the second station is associated with the WLAN. ### Claim 22 (depends on 20) The method of claim 20, wherein the GAS protocol element includes an info ID field indicating whether the GAS protocol element is related to the channel availability information or not. ### Claim 23 (depends on 20) The method of claim 20, wherein: the request frame is a GAS initial request frame; and the response frame is a GAS initial response frame. ### Claim 24 (depends on 20) The method of claim 20, wherein the CAQ response includes a GAS protocol element including a white space map (WSM) including the information on the available frequencies. ### Claim 25 (depends on 24) The method of claim 24, wherein the database provides a list of available channels for the location of the first station or the second station. ### Claim 26 (depends on 25) The method of claim 25, wherein the WSM includes the information on the available frequencies for a location of the first station or the second station. ### Claim 27 (depends on 20) The method of claim 20, wherein the GAS protocol element is a Registered Location Query Protocol (RLQP) element. ### Claim 28 (depends on 20) The method of claim 20, further comprising: transmitting, by the first station to the second station, an enabling signal; receiving, by the first station from the second station, an enablement request frame; and transmitting, by the first station to the second station, an enablement response frame, wherein the enablement response frame includes the WSM. ### Claim 29 (depends on 20) The method of claim 20, wherein: the first station is an enabling station; and the second station is a dependent station. ### Claim 30 (depends on 20) The method of claim 20, wherein: the first station is a CAQ responding station; and the second station is a CAQ requesting station. ### Claim 31 A method for performing procedures for interworking with external networks in a wireless local area network (WLAN), the method comprising: receiving, by a second station from a first station, an advertisement protocol element indicating support for a specific generic advertisement service (GAS) protocol; transmitting, by the second station to the first station, a channel availability query (CAQ) request including a GAS protocol element; and receiving, by the second station from the first station, a CAQ response including channel availability information, wherein the first station accesses a database to obtain information on available frequencies. ### Claim 32 An apparatus of a first station for performing procedures for interworking with external networks in a wireless local area network (WLAN), the apparatus comprising: a transceiver; and a processor configured to: transmit, to a second station, an advertisement protocol element indicating support for a specific generic advertisement service (GAS) protocol; receive, from the second station, a channel availability query (CAQ) request including a GAS protocol element; access a database to obtain information on available frequencies; and transmit, by the first station to the second station, a CAQ response including channel availability information. ### Claim 33 An apparatus of a second station for performing procedures for interworking with external networks in a wireless local area network (WLAN), the apparatus comprising: a transceiver; and a processor configured to: receive, from a first station, an advertisement protocol element indicating support for a specific generic advertisement service (GAS) protocol; transmit, to the first station, a channel availability query (CAQ) request including a GAS protocol element; and receive, from the first station, a CAQ response including channel availability information, wherein the first station accesses a database to obtain information on available frequencies.