# US 11,451,987 B2 · Channel availability check optimization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,987 B2 - Document ID: US11451987B2 - Status: Granted - Kind: B2 - Application number: 17/148,640 - Filed: 2021-01-14 - Published: 2022-07-14 - Granted: 2022-09-20 - Earliest claimed: 2021-01-14 - Assignees: Cisco Technology, Inc. - Applicants: Cisco Technology, Inc. - Inventors: Vishal Satyendra Desai; Edgard Vangeel; Jerome Henry; Robert E. Barton - Web page: https://patentgrep.com/patent/US11451987B2 ## CPC - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W 24/06: Testing, {supervising or monitoring} using simulated traffic - G01S 7/021: {Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals} - H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information} - H04L 27/0006: {Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio (for spectrum sharing between different networks H04W16/14)} - H04W 88/08: Access point devices - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Channel availability check optimization may be provided. A plurality of Pulse Repetition Intervals (PRIs) may be determined for a respective plurality of bursts on a respective plurality of frequencies. A list of at least a portion of the plurality of frequencies may be generated. The list may include a plurality of bias factors respectively indicating a probability that each of the respective plurality of bursts was a radar burst based on the respective plurality of PRIs. An Access Point (AP) may perform a plurality of preemptive Channel Availability Checks (CACs) on each of the respective plurality of frequencies on the list in order of highest probability to lowest probability based on the plurality of bias factors. ## Claims ### Claim 1 A method comprising: determining a plurality of Pulse Repetition Intervals (PRIs) for a respective plurality of bursts on a respective plurality of frequencies; generating a list of at least a portion of the plurality of frequencies wherein the list includes a plurality of bias factors respectively indicating a probability that each of the respective plurality of bursts was a radar burst based on the respective plurality of PRIs; and causing an Access Point (AP) to perform a plurality of preemptive Channel Availability Checks (CACs) on each of the respective plurality of frequencies on the list in order of highest probability to lowest probability based on the plurality of bias factors. ### Claim 2 (depends on 1) The method of claim 1, wherein generating the list comprises generating the list wherein only the plurality of frequencies having bias factors greater than a predetermined value are included on the list. ### Claim 3 (depends on 1) The method of claim 1, wherein causing the AP to perform the plurality of preemptive CACs comprises causing the AP to perform a CAC on adjacent frequencies when the bias factors of the adjacent frequencies are similar. ### Claim 4 (depends on 1) The method of claim 1, wherein causing the AP to perform the plurality of preemptive CACs comprises causing the AP to perform the plurality of preemptive CACs comprising full CACs. ### Claim 5 (depends on 1) The method of claim 1, wherein causing the AP to perform the plurality of preemptive CACs comprises causing the AP to perform the plurality of preemptive CACs comprising off-channel CACs. ### Claim 6 (depends on 1) The method of claim 1, further comprising placing frequencies requiring longer CAC times higher on the list than frequencies requiring shorter CAC times. ### Claim 7 (depends on 1) The method of claim 1, further comprising using information from neighboring radios to one of increase one of the plurality of bias factors and decrease one of the plurality of bias factors. ### Claim 8 A system comprising: a memory storage; and a processing unit, the processing unit coupled to the memory storage, wherein the processing unit is operative to: determine a plurality of Pulse Repetition Intervals (PRIs) for a respective plurality of bursts on a respective plurality of frequencies; generate a list of at least a portion of the plurality of frequencies wherein the list includes a plurality of bias factors respectively indicating a probability that each of the respective plurality of bursts was a radar burst based on the respective plurality of PRIs; and cause a plurality of preemptive Channel Availability Checks (CACs) on each of the respective plurality of frequencies on the list in order of highest probability to lowest probability based on the plurality of bias factors. ### Claim 9 (depends on 8) The system of claim 8, wherein only the plurality of frequencies having bias factors greater than a predetermined value are included on the list. ### Claim 10 (depends on 8) The system of claim 8, wherein the processing unit being operative to cause the plurality of preemptive CACs comprises the processing unit being operative to cause a CAC on adjacent frequencies when the bias factors of the adjacent frequencies are similar. ### Claim 11 (depends on 8) The system of claim 8, wherein the processing unit being operative to cause the plurality of preemptive CACs comprises the processing unit being operative to cause the plurality of preemptive CACs comprising full CACs and the plurality of preemptive CACs comprising off-channel CACs. ### Claim 12 (depends on 8) The system of claim 8, wherein the processing unit is further operative to place frequencies requiring longer CAC times higher on the list than frequencies requiring shorter CAC times. ### Claim 13 (depends on 8) The system of claim 8, wherein the processing unit is further operative to use information from neighboring radios to one of increase one of the plurality of bias factors and decrease one of the plurality of bias factors. ### Claim 14 A non-transitory computer-readable medium that stores a set of instructions which when executed perform a method executed by the set of instructions comprising: determining a plurality of Pulse Repetition Intervals (PRIs) for a respective plurality of bursts on a respective plurality of frequencies; generating a list of at least a portion of the plurality of frequencies wherein the list includes a plurality of bias factors respectively indicating a probability that each of the respective plurality of bursts was a radar burst based on the respective plurality of PRIs; and causing an Access Point (AP) to perform a plurality of preemptive Channel Availability Checks (CACs) on each of the respective plurality of frequencies on the list in order of highest probability to lowest probability based on the plurality of bias factors. ### Claim 15 (depends on 14) The non-transitory computer-readable medium of claim 14, wherein generating the list comprises generating the list wherein only the plurality of frequencies having bias factors greater than a predetermined value are included on the list. ### Claim 16 (depends on 14) The non-transitory computer-readable medium of claim 14, wherein causing the AP to perform the plurality of preemptive CACs comprises causing the AP to perform a CAC on adjacent frequencies when the bias factors of the adjacent frequencies are similar. ### Claim 17 (depends on 14) The non-transitory computer-readable medium of claim 14, wherein causing the AP to perform the plurality of preemptive CACs comprises causing the AP to perform the plurality of preemptive CACs comprising full CACs. ### Claim 18 (depends on 14) The non-transitory computer-readable medium of claim 14, wherein causing the AP to perform the plurality of preemptive CACs comprises causing the AP to perform the plurality of preemptive CACs comprising off-channel CACs. ### Claim 19 (depends on 14) The non-transitory computer-readable medium of claim 14, further comprising placing frequencies requiring longer CAC times higher on the list than frequencies requiring shorter CAC times. ### Claim 20 (depends on 14) The non-transitory computer-readable medium of claim 14, further comprising using information from neighboring radios to one of increase one of the plurality of bias factors and decrease one of the plurality of bias factors.