# US 2013/0155980 A1 · Orthogonal frequency division multiple access with carrier sense > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0155980 A1 - Document ID: US20130155980A1 - Status: Published application - Kind: A1 - Application number: 13/763,671 - Filed: 2013-02-09 - Published: 2013-06-20 - Earliest claimed: 2008-01-25 - Assignees: Microsoft Corporation - Inventors: Amer A. Hassan; Adam Sapek; Hui Shen; Thomas W. Kuehnel; Deyun Wu; Christian Huitema - Web page: https://patentgrep.com/patent/US20130155980A1 ## CPC - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 5/0037: {Inter-user or inter-terminal allocation} - H04L 5/0094: {Indication of how sub-channels of the path are allocated} - 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 72/04: Wireless resource allocation - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04L 5/0064: {Rate requirement of the data, e.g. scalable bandwidth, data priority} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A communication system in which an access point and one or more devices communicating through the access point adaptively apply Orthogonal Frequency Division Multiple Access (OFDMA). The access point may assign orthogonal subcarriers to devices as in conventional OFDMA, but the access point senses activity on the subcarriers and selects subcarriers without activity for assignment. In an alternative approach, a device that is configured for OFDMA communication may receive a channel assignment from a device that does not support OFDMA. The OFDMA-capable device may use only a portion of the subcarriers in the assigned channel, which may be communicated to the non-OFDMA device. During the non-OFDMA device may then ignore unused subcarriers in error detection and correction to avoid incorrectly classifying communications as erroneous. Information about OFDMA capabilities, subcarrier assignments and subcarriers in use may be communicated as information elements in network control communications, such as beacons and probe messages. ## Claims ### Claim 1 A method performed on a computing device, the method comprising: assigning a set of individual subcarriers to another device; and modifying error detection and correction processing of the computing device where, for messages received from the another device via a subset of the assigned set, any of the individual subcarriers of the assigned set that are not part of the subset used to send the messages will not result in message errors. ### Claim 2 (depends on 1) The method of claim 1 where the computing device compromises a wireless access point. ### Claim 3 (depends on 1) The method of claim 1 where the assigning includes sending an assignment of the set as part of a beacon transmission. ### Claim 4 (depends on 1) The method of claim 1 further comprising repeating the method based on signal activity levels. ### Claim 5 (depends on 1) The method of claim 1 further comprising receiving an indication from the another device identifying the any of the individual subcarriers of the assigned set that are not part of the subset used to send the messages. ### Claim 6 (depends on 5) The method of claim 5 where the modifying is based at least in part on the received indication. ### Claim 7 (depends on 1) The method of claim 1 embodied as computer-executable instructions stored on a computer storage device. ### Claim 8 A computing device and at least one software module together configured for performing act ns comprising: assigning a set of individual subcarriers to another device; and modifying error detection and correction processing of the computing device where, for messages received from the another device via a subset of the assigned set, any of the individual subcarriers of the assigned set that are not part of the subset used to send the messages will not result in message errors. ### Claim 9 (depends on 8) The computing device and at least one software module of claim 8 where the computing device compromises a wireless access point. ### Claim 10 (depends on 8) The computing device and at least one software module of claim 8 where the assigning includes sending an assignment of the set as part of a beacon transmission. ### Claim 11 (depends on 8) The computing device and at least one software module of claim 8, the actions further comprising repeating the method based on signal activity levels. ### Claim 12 (depends on 8) The computing device and at least one software module of claim 8, the actions further comprising receiving an indication from the another device identifying the any of the individual subcarriers of the assigned set that are not part of the subset used to send the messages. ### Claim 13 (depends on 12) The computing device and at least one software module of claim 12 where the modifying is based at least in part on the received indication. ### Claim 14 (depends on 8) The computing device and at least one software module of claim 8 where the subset of the assigned set further comprises at least one subcarrier from a different set than the assigned set. ### Claim 15 A method performed on a computing device, the method comprising: receiving, from another device, an assignment indicating a set of individual subcarriers; and sending, to the another device, messages via a subset of the indicated set of individual subcarriers, where any of the individual subcarriers of the set that are not part of the subset used to send the messages will not cause message errors at the another computing device. ### Claim 16 (depends on 15) The method of claim 15 where the computing device compromises a wireless client device. ### Claim 17 (depends on 15) The method of claim 15 where the receiving includes receiving the assignment indicating the set as part of a beacon transmission. ### Claim 18 (depends on 15) The method of claim 15 further comprising repeating the method based on signal activity levels. ### Claim 19 (depends on 15) The method of claim 15 further comprising sending an indication to the another device identifying the any of the individual subcarriers of the set that are not part of the subset used to send the messages. ### Claim 20 (depends on 15) The method of claim 15 embodied as computer-executable instructions stored on a computer storage device.