# US 2013/0155848 A1 · Link adaptation 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 2013/0155848 A1 - Document ID: US20130155848A1 - Status: Published application - Kind: A1 - Application number: 13/767,807 - Filed: 2013-02-14 - Published: 2013-06-20 - Earliest claimed: 2008-12-31 - Assignees: STMicroelectronics S.r.l. - Inventors: Nicola Baldo; Federico Maguolo; Simone Merlin; Andrea Zanella; Michele Zorzi; David Siorpaes - Web page: https://patentgrep.com/patent/US20130155848A1 ## CPC - H04W 84/12: WLAN [Wireless Local Area Networks] - H04L 1/0002: {by adapting the transmission rate} - H04L 1/0019: {in which mode-switching is based on a statistical approach} - H04L 27/0008: {arrangements for allowing a transmitter or receiver to use more than one type of modulation (negotiating modulation type for two-way transmission paths H04L5/1453)} - H04L 43/0829: Packet loss - H04L 43/0894: Packet rate - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract An embodiment of a system for physical link adaptation in a wireless communication network such as e.g., a WLAN, selectively varies the physical mode of operation of the transmission channels serving the mobile stations in the network. The system includes an estimation module to evaluate transmission losses due to collisions as well as transmission losses due to channel errors over the transmission channel, and an adaptation module to select the physical mode of operation of the transmission channel as a function of the transmission losses due to collisions and to channel errors as evaluated by the estimation module. ## Claims ### Claim at position 1 1-44. (canceled) ### Claim 45 A method, comprising: determining a collision-failure probability that a first unit will not receive first data transmitted over a wireless channel due to an overlapping transmission of second data over the channel; determining a channel-failure probability that the first unit will not receive the first data due to a characteristic of the channel; and selecting in response to the collision- and channel-failure probabilities a value for a data-transmission parameter for transmitting data to the first unit. ### Claim 46 (depends on 45) The method of claim 45 wherein determining the collision-failure probability comprises determining the collision-failure probability that the first unit will not receive the first data transmitted by a second unit due to an overlapping transmission of the second data by a third unit. ### Claim 47 (depends on 45) The method of claim 45 wherein determining the collision-failure probability comprises determining the collision-failure probability from a value generated by a medium-access-control counter. ### Claim 48 (depends on 45) The method of claim 45 wherein determining the collision-failure probability comprises determining the collision-failure probability from a change in a value generated by a medium-access-control counter. ### Claim 49 (depends on 45) The method of claim 45 wherein determining the channel-failure probability comprises determining the channel-failure probability from the collision-failure probability. ### Claim 50 (depends on 45) The method of claim 45 wherein determining the channel-failure probability comprises determining the channel-failure probability from a number of data transmissions to the first unit that are not acknowledged by the first unit as being received. ### Claim 51 (depends on 45) The method of claim 45, further comprising: determining a signal-to-noise ratio of the channel from the channel-failure probability; and selecting the value of the data-transmission parameter in response to the collision-failure probability and the signal-to-noise ratio. ### Claim 52 (depends on 45) The method of claim 45 wherein the characteristic of the channel comprises noise. ### Claim 53 (depends on 45) The method of claim 45 wherein selecting the value of the data-transmission parameter comprises selecting the value of the data-transmission parameter from a look-up table. ### Claim 54 (depends on 45) The method of claim 45 wherein selecting the value of the data-transmission parameter comprises calculating the value of the data-transmission parameter. ### Claim 55 (depends on 45) The method of claim 45 wherein the data-transmission parameter comprises a rate at which data is transmitted to the first unit. ### Claim 56 (depends on 45) The method of claim 45 wherein selecting the value of the data-transmission parameter comprises: calculating respective data-transmission throughputs from the collision- and channel-failure probabilities over a range of values of the data-transmission parameter; and selecting as the value of the data-transmission parameter the value corresponding to the highest calculated data-transmission throughput. ### Claim 57 (depends on 45) The method of claim 45 wherein selecting the value of the data-transmission parameter comprises: calculating respective data-transmission throughputs from the collision- and channel-failure probabilities over a range of values of the data-transmission parameter; selecting as the value of the data-transmission parameter the value corresponding to the highest calculated data-transmission throughput. ### Claim 58 (depends on 45) The method of claim 45 wherein selecting the value of the first data-transmission parameter comprises: calculating respective estimated channel-failure probabilities from the collision- and channel-failure probabilities over a range of values of the first data-transmission parameter; and selecting as the value of the data-transmission parameter the value corresponding to the lowest channel-failure probability. ### Claim 59 (depends on 45) The method of claim 45, further comprising: determining a value from the collision- and channel-failure probabilities and a number of data transmissions to the first unit that are not acknowledged by the first unit as being received; and updating the channel-failure probability using the value. ### Claim 60 (depends on 45) The method of claim 45, further comprising: determining a value from the collision- and channel-failure probabilities and from a number of data transmissions to the first unit that are not acknowledged by the first unit as being received; generating a substantially random number; incrementing the value only if another data transmission to the first unit is not acknowledged by the first unit as being received and if the random number has a predetermined relationship to a predetermined mathematical combination of the collision- and channel-failure probabilities; and updating the channel-failure probability using the value. ### Claim 61 A communication unit, comprising: a transmitter; a first module operable to determine a collision-failure probability that a remote unit will not receive first data transmitted from the transmitter over a wireless channel due to an overlapping transmission of second data over the channel, and to determine a channel-failure probability that the remote unit will not receive the first data due to a characteristic of the channel; and a second module operable to select in response to the collision- and channel-failure probabilities a value for a data-transmission parameter according to which the transmitter transmits data to the remote unit. ### Claim 62 (depends on 61) The communication unit of claim 61 wherein at least one of the first and second modules comprises a respective software component. ### Claim 63 (depends on 61) The communication unit of claim 61 wherein at least one of the first and second modules comprises a respective hardware component. ### Claim 64 (depends on 51) The communication unit of claim 51, further comprising a receiver operable to receive data transmitted by the remote unit. ### Claim 65 (depends on 51) The communication unit of claim 51, further comprising: a memory operable to store values of the data-transmission parameter corresponding to respective pairs of values of the collision- and channel-failure probabilities; and wherein the second module is operable to select the value of the data-transmission parameter from a storage location of the memory that corresponds to the determined values of the collision- and channel-failure probabilities. ### Claim 66 A computer-readable medium storing program instructions that when executed by a processor, cause the processor: to determine a collision-failure probability that a first unit will not receive first data transmitted over a wireless channel due to an overlapping transmission of second data over the channel; to determine a channel-failure probability that the first unit will not receive the first data due to a characteristic of the channel; and to select in response to the collision- and channel-failure probabilities a value for a data-transmission parameter for transmitting data to the first unit.