# US 2014/0192820 A1 · Methods and arrangements to mitigate collisions in wireless networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192820 A1 - Document ID: US20140192820A1 - Status: Published application - Kind: A1 - Application number: 13/931,918 - Filed: 2013-06-29 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Intel IP Corporation - Inventors: Shahrnaz Azizi; Adrian P. Stephens; Thomas J. Kenney; Eldad Perahia; Minyoung Park - Web page: https://patentgrep.com/patent/US20140192820A1 ## CPC - H04W 72/04: Wireless resource allocation - C12N 15/74: Vectors or expression systems specially adapted for prokaryotic hosts other than E. coli, e.g. Lactobacillus, Micromonospora - H04W 74/0816: with collision avoidance - H04W 84/18: Self-organising networks, e.g. ad-hoc networks or sensor networks - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00) ## Abstract Logic for collision mitigation between transmissions of wireless transmitters and receivers operating at different bandwidths. Logic of the receivers may be capable of receiving and detecting signals transmitted at narrower bandwidths. In several embodiments, the receivers comprise a clear channel assessment logic that implements a guard interval (or cyclic prefix) detector to detect transmissions at narrower bandwidths. For instance, a two MegaHertz (MHz) bandwidth receiver may implement a guard interval detector to detect 1 MHz bandwidth signals and a 16M Hz bandwidth receiver may implement logic to detect one or more 1 MHz bandwidth signals and any other combination of, e.g., 1, 2, 4, 8 MHz bandwidth signals. In many embodiments, the guard interval detector may be implemented to detect guard intervals on a channel designated as a primary channel as well as on one or more non-primary channels. ## Claims ### Claim 1 A method to mitigate collisions between transmissions of devices operating at different bandwidths on a primary frequency of operation, the method comprising: performing guard interval detection on a primary channel on the primary frequency in addition to start of the packet detection and energy detection on the primary channel and guard interval detection on a non-primary channel on the primary frequency to determine if a medium is busy in response to entering an active mode from a power-save mode; determining whether the medium is busy based upon the performing; and outputting an indication that the medium is busy to defer transmissions for a period of time in response to determining that the medium is busy. ### Claim 2 (depends on 1) The method of claim 1, further comprising outputting a clear channel assessment indicating that the medium is not busy in response to determining that the medium is not busy. ### Claim 3 (depends on 1) The method of claim 1, further comprising: determining whether a station has transitioned from the power save mode to the active mode; determining whether a network allocation vector is unexpired; and following start of packet detection and energy detection and guard interval detection on a non-primary channel of the primary frequency rules if the station did not enter the active mode from the power-saving mode or if there is an indication that the network allocation vector is updated. ### Claim 4 (depends on 1) The method of claim 1, further comprising determining that a network allocation vector is not updated. ### Claim 5 (depends on 1) The method of claim 1, wherein performing the guard interval detection on the primary channel of the primary frequency comprises: receiving, by a device, a signal on the primary frequency; selecting the signal on the primary channel; and correlating the signal on the primary channel to detect a guard interval in the signal on the primary channel. ### Claim 6 (depends on 5) The method of claim 5, wherein correlating comprises comparing peaks in the correlation to determine if one or more peaks are greater than a threshold correlation value. ### Claim 7 (depends on 5) The method of claim 5, wherein correlating comprises correlating the signal on the primary channel against a delayed version of the signal on the primary channel. ### Claim 8 A device to mitigate collisions between transmissions of devices operating at different bandwidths on a primary frequency of operation, the device comprising: a radio; and clear channel assessment (CCA) logic coupled with the radio to perform guard interval detection on a primary channel of the primary frequency in addition to start of packet detection and energy detection on the primary channel and guard interval detection on a non-primary channel on the primary frequency to determine if a medium is busy in response to entering an active mode from a power-save mode; determine whether the medium is busy based upon the performing; and to output a clear channel assessment indicating that the medium is busy to defer transmissions for a period of time in response to determining that the medium is busy. ### Claim 9 (depends on 8) The device of claim 8, further comprising logic to select the signal on the primary channel. ### Claim 10 (depends on 8) The device of claim 8, wherein the CCA logic comprises logic to indicate a clear channel assessment if the medium is not busy. ### Claim 11 (depends on 8) The device of claim 8, wherein the CCA logic comprises logic to determine whether a station has transitioned from the power save mode to the active mode; determine whether a network allocation vector is unexpired; and follow start of the packet detection and energy detection and guard interval detection on a non-primary channel of the primary frequency rules if the station did not enter the active mode from the power-saving mode or if there is an indication that the network allocation vector is updated. ### Claim 12 (depends on 8) The device of claim 8, wherein the CCA logic comprises guard interval logic to receive a signal on the primary frequency; select the signal on the primary channel; and correlate the signal on the primary channel to detect a guard interval in the signal on the primary channel. ### Claim 13 (depends on 8) The device of claim 8, wherein the CCA logic comprises guard interval logic to compare peaks in the correlation to determine if one or more peaks are greater than a threshold correlation value. ### Claim 14 (depends on 8) The device of claim 8, wherein the CCA logic comprises guard interval logic to correlate the signal on the primary channel against a delayed version of the signal on the primary channel. ### Claim 15 A system to mitigate collisions between transmissions of devices operating at different bandwidths on a primary frequency of operation, the device comprising: a medium access control logic to generate a frame for transmission; a receiver comprising clear channel assessment (CCA) logic to perform guard interval detection on a primary channel of the primary frequency in addition to start of packet detection and energy detection on the primary channel and guard interval detection on a non-primary channel of the primary frequency to determine if a medium is busy in response to entering an active mode from a power-save mode; determine whether the medium is busy based upon the performing; and output an indication that the medium is busy to defer transmissions for a period of time in response to detecting a guard interval on the primary channel; and a transmitter to defer transmissions for a period of time in response to determining that the medium is busy. ### Claim 16 (depends on 15) The system of claim 15, further comprising an antenna coupled with the receiver to receive a signal. ### Claim 17 (depends on 15) The system of claim 15, wherein the CCA logic comprises logic to determine whether a station has transitioned from the power save mode to the active mode; determine whether an network allocation vector is unexpired; and follow start of the packet detection and energy detection and guard interval detection on a non-primary channel of the primary frequency rules if the station did not enter the active mode from the power-saving mode or if there is an indication that the network allocation vector is updated. ### Claim 18 (depends on 15) The system of claim 15, wherein the CCA logic comprises guard interval logic to receive a signal on the primary frequency; select the signal on the primary channel; and correlate the signal on the primary channel to detect a guard interval in the signal. ### Claim 19 (depends on 15) The system of claim 15, wherein the CCA logic comprises guard interval logic comprises logic to compare peaks in the correlation to determine if one or more peaks are greater than a threshold correlation value. ### Claim 20 A machine-accessible product comprising: a medium containing instructions to mitigate collisions between transmissions of devices operating at different bandwidths on a primary frequency of operation, wherein the instructions, when executed, cause a receiver to perform operations, the operations comprising: performing guard interval detection on a primary channel on the primary frequency in addition to start of the packet detection and energy detection on the primary channel and guard interval detection on a non-primary channel on the primary frequency to determine if a medium is busy in response to entering an active mode from a power-save mode; determining whether the medium is busy based upon the performing; and outputting a clear channel assessment to defer transmissions for a period of time in response to determining that the medium is busy. ### Claim 21 (depends on 20) The machine-accessible product of claim 20, wherein the operations further comprise indicating a clear channel assessment that the medium is not busy if the medium is not busy. ### Claim 22 (depends on 20) The machine-accessible product of claim 20, wherein the operations further comprise: determining whether a station has transitioned from the power save mode to the active mode; determining whether an network allocation vector is unexpired; and following start of the packet detection and energy detection and guard interval detection on a non-primary channel of the primary frequency rules if the station did not enter the active mode from the power-saving mode or if there is an indication that the network allocation vector is updated. ### Claim 23 (depends on 20) The machine-accessible product of claim 20, wherein performing the guard interval detection on the primary channel of the primary frequency comprises: receiving, by a device, a signal on the primary frequency; selecting the signal on the primary channel; and correlating the primary channel to detect a guard interval in the signal. ### Claim 24 (depends on 23) The machine-accessible product of claim 23, wherein correlating comprises comparing peaks in the correlation to determine if one or more peaks are greater than a threshold correlation value. ### Claim 25 (depends on 23) The machine-accessible product of claim 23, wherein correlating comprises correlating the primary channel against a delayed version of the primary channel.