Link adaptation using transmission rate options

Abstract

This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for link adaptation in a wireless local area network (WLAN). A link adaptation test packet from a first WLAN device to a second WLAN may include a plurality of link adaptation test portions that are generated using a corresponding plurality of transmission rate options. For example, the plurality of link adaptation test portions may be modulated using different modulation and coding scheme (MCS) options. Thus, a single test packet may be used to evaluate different transmission rate options. The second WLAN device may provide feedback information regarding the link adaptation test portions. The feedback information may be used to determine a transmission rate for a subsequent transmission from the first WLAN device to the second WLAN device based on wireless channel conditions.

What is claimed is: 
     
         1 . An apparatus of a first wireless device, comprising:
 one or more memories storing processor-executable code; and   one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the first wireless device to:
 transmit, to a second wireless device, a first packet that includes a plurality of link adaptation test portions generated using a plurality of transmission rate options; 
 receive, from the second wireless device, feedback information based at least in part on the first packet; and 
 transmit, to the second wireless device and based at least in part on the feedback information, a subsequent packet using a first transmission rate option of the plurality of transmission rate options. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the plurality of link adaptation test portions including a first portion modulated using a first modulation and coding scheme (MCS) and a second portion modulated using a second MCS. 
     
     
         3 . The apparatus of  claim 1 , wherein the first packet has a format based at least in part on a null data packet (NDP) defined for a wireless local area network (WLAN) associated with the first wireless device. 
     
     
         4 . The apparatus of  claim 1 , wherein the first packet includes an indication to cause the second wireless device to receive the plurality of link adaptation test portions using the plurality of transmission rate options and provide the feedback information based at least in part on the plurality of link adaptation test portions. 
     
     
         5 . The apparatus of  claim 1 , wherein the first packet is a dedicated link adaptation test packet having a format specified by a link adaptation protocol. 
     
     
         6 . The apparatus of  claim 1 , wherein the first packet further comprises upper layer data for the second wireless device. 
     
     
         7 . The apparatus of  claim 6 , wherein the upper layer data is included in a separate portion of the first packet that is different from the plurality of link adaptation test portions. 
     
     
         8 . The apparatus of  claim 1 , wherein the plurality of link adaptation test portions includes a first portion that is modulated in a first set of tones of an orthogonal frequency division multiplexed (OFDM) symbol and a second portion that is modulated in a second set of tones of the OFDM symbol. 
     
     
         9 . The apparatus of  claim 1 , wherein the plurality of link adaptation test portions includes a first portion and a second portion of the first packet, the first portion and the second portion being modulated in different orthogonal frequency division multiplexed (OFDM) symbols associated with the first packet. 
     
     
         10 . The apparatus of  claim 9 , wherein the first packet includes a series of OFDM symbols, each OFDM symbol being modulated using a different transmission rate option of the plurality of transmission rate options. 
     
     
         11 . The apparatus of  claim 1 , wherein the feedback information indicates the first transmission rate option selected by the second wireless device. 
     
     
         12 . The apparatus of  claim 1 , wherein the feedback information indicates one or more link quality metrics related to the plurality of link adaptation test portions, and the first transmission rate option is based at least in part on the one or more link quality metrics. 
     
     
         13 . The apparatus of  claim 12 , wherein the one or more link quality metrics include at least one member selected from a group consisting of:
 a signal to noise ratio (SNR),   a signal to interference plus noise ratio (SINR), or   an error vector magnitude (EVM).   
     
     
         14 . The apparatus of  claim 1 , wherein:
 to receive the feedback information, the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to receive an acknowledgement (ACK) message in response to the first packet; and   the ACK message includes a field populated with the feedback information.   
     
     
         15 . The apparatus of  claim 1 , wherein:
 the first packet is a request to send (RTS) packet;   to receive the feedback information, the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to receive a clear to send (CTS) message in response to the RTS packet; and   the CTS message includes a field populated with the feedback information.   
     
     
         16 . The apparatus of  claim 1 , wherein:
 each of the plurality of link adaptation test portions is modulated using a different modulation and coding scheme (MCS);   the feedback information includes a log likelihood ratio (LLR) metric indicative of a decoding success rate for each of the plurality of link adaptation test portions; and   the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to select a first MCS associated with a link adaptation test portion having a highest throughput and for which a corresponding LLR metric is above a threshold.   
     
     
         17 . An apparatus of a second wireless device, comprising:
 one or more memories storing processor-executable code; and   one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the second wireless device to:
 receive, from a first wireless device via a wireless channel, a first packet that includes a plurality of link adaptation test portions generated using a plurality of transmission rate options; 
 transmit, to the first wireless device, feedback information based at least in part on the plurality of link adaptation test portions; and 
 receive, from the first wireless device via the wireless channel and based at least in part on the feedback information, a subsequent packet transmitted using a first transmission rate option of the plurality of transmission rate options. 
   
     
     
         18 . The apparatus of  claim 17 , wherein the plurality of link adaptation test portions includes a first portion modulated using a first modulation and coding scheme (MCS) and a second portion modulated using a second MCS. 
     
     
         19 . The apparatus of  claim 17 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to:
 select the first transmission rate option based at least in part on the plurality of link adaptation test portions.   
     
     
         20 . A method for wireless communication at a first wireless device, comprising:
 transmitting, to a second wireless device via a wireless channel, a first packet that includes a plurality of link adaptation test portions generated using a plurality of transmission rate options;   receiving, from the second wireless device, feedback information based at least in part on the plurality of link adaptation test portions; and   transmitting, to the second wireless device via the wireless channel and based at least in part on the feedback information, a subsequent packet using a first transmission rate option of the plurality of transmission rate options.