Abstract: Methods, systems, and devices for wireless communication are described. In some systems (e.g., Wi-Fi systems), a transmitting device such as an access point (AP) or mobile station (STA), may identify a number of spatial streams for a data transmission that is less than a number of transmit antennas, and may transmit a packet over a channel. In a first implementation, the packet may be formatted in a multi-user frame format, with a number of long training field (LTF) symbols equal to the number of transmit antennas. In a second implementation, the packet may be a null data packet (NDP), and the device may transmit a separate data packet. In a third implementation, the packet may be formatted in single-user frame format with a modified LTF. A receiving device may receive the packet, and may perform channel estimation and power amplifier (PA) distortion cancellation based on the received packet.

Abstract: Methods, systems, and devices for wireless communication are described. In some systems (e.g., Wi-Fi systems), a transmitting device such as an access point (AP) or mobile station (STA), may identify a number of spatial streams for a data transmission that is less than a number of transmit antennas, and may transmit a packet over a channel. In a first implementation, the packet may be formatted in a multi-user frame format, with a number of long training field (LTF) symbols equal to the number of transmit antennas. In a second implementation, the packet may be a null data packet (NDP), and the device may transmit a separate data packet. In a third implementation, the packet may be formatted in single-user frame format with a modified LTF. A receiving device may receive the packet, and may perform channel estimation and power amplifier (PA) distortion cancellation based on the received packet.

Abstract: Methods, systems, and devices for wireless communication are described. In some systems (e.g., Wi-Fi systems), a transmitting device such as an access point (AP) or mobile station (STA), may identify a number of spatial streams for a data transmission that is less than a number of transmit antennas, and may transmit a packet over a channel. In a first implementation, the packet may be formatted in a multi-user frame format, with a number of long training field (LTF) symbols equal to the number of transmit antennas. In a second implementation, the packet may be a null data packet (NDP), and the device may transmit a separate data packet. In a third implementation, the packet may be formatted in single-user frame format with a modified LTF. A receiving device may receive the packet, and may perform channel estimation and power amplifier (PA) distortion cancellation based on the received packet.

Abstract: Apparatuses and methods for correcting a distorted signal at a receiver device during wireless local area network (WLAN) communications are disclosed. The apparatuses and methods include receiving, by a receiver device in a WLAN, a distorted signal corresponding to a data packet signal transmitted from a transmitter device, receiving, by the receiver device, one or more transmitter parameters corresponding to the transmission of the data packet signal, the one or more transmitter parameters including information to adjust the distorted signal, and adjusting, by the receiver device, the distorted signal to reconstruct the data packet signal based at least on the one or more transmitter parameters.

Abstract: This disclosure provides methods, devices and systems for obtaining and providing channel feedback. In some implementations, a beamformee provides channel feedback to a beamformer that enables the beamformer to construct and independently precode two or more different sets of spatial streams for transmission to the beamformee. The independent precoding of the different sets of spatial streams ensures that the decodings of the different sets of spatial streams may be decoupled from one another at the beamformee. To provide the channel feedback, the beamformee partitions a channel estimate into two or more sub-estimates prior to performing a channel decomposition. In some implementations, the beamformee determines null-space-based projections of the sub-estimates before performing the channel decomposition.

Abstract: Systems and methods are disclosed that may detect data transmitted using MIMO communications. MIMO signals may be received via a wireless channel. Channel conditions may be estimated for the wireless channel based at least in part on the received MIMO signals. Each tone of the received MIMO signals may then be processed according to either a first receiver algorithm or a second receiver algorithm based at least in part on the estimated channel conditions, where the second receiver algorithm has a greater complexity and a greater accuracy than the first receiver algorithm.

Abstract: Methods, systems, and devices for wireless communication are described. In some systems (e.g., Wi-Fi systems), a transmitting device such as an access point (AP) or mobile station (STA), may identify a number of spatial streams for a data transmission that is less than a number of transmit antennas, and may transmit a packet over a channel. In a first implementation, the packet may be formatted in a multi-user frame format, with a number of long training field (LTF) symbols equal to the number of transmit antennas. In a second implementation, the packet may be a null data packet (NDP), and the device may transmit a separate data packet. In a third implementation, the packet may be formatted in single-user frame format with a modified LTF. A receiving device may receive the packet, and may perform channel estimation and power amplifier (PA) distortion cancellation based on the received packet.

Abstract: Apparatuses and methods for correcting a distorted signal at a receiver device during wireless local area network (WLAN) communications are disclosed. The apparatuses and methods include receiving, by a receiver device in a WLAN, a distorted signal corresponding to a data packet signal transmitted from a transmitter device, receiving, by the receiver device, one or more transmitter parameters corresponding to the transmission of the data packet signal, the one or more transmitter parameters including information to adjust the distorted signal, and adjusting, by the receiver device, the distorted signal to reconstruct the data packet signal based at least on the one or more transmitter parameters.

Abstract: A device includes one or more antennas configured to receive a first signal and a second signal from a second device. The first signal includes a non-precoded signal. The device further includes a receiver coupled to the one or more antennas. The receiver is configured to determine a first channel estimate based on the first signal and determine a second channel estimate based on the second signal. The receiver is also configured to determine an estimated distortion based at least in part on the first channel estimate and the second channel estimate. The receiver is further configured to perform a distortion reduction operation on the second signal based on the estimated distortion to generate a reduced-distortion signal.

Abstract: A method includes receiving a signal at a receiver device via a channel from a transmitter device and determining a frequency domain representation of the signal. The signal includes multiple modulation symbols. The method further includes detecting a first symbol of the signal and determining a time domain representation of a distortion estimate associated with the first symbol using a distortion recovery receiver (DRR) technique. The method further includes subtracting the distortion estimate from the first symbol to generate an updated estimate of the first symbol. The method further includes determining a frequency domain representation of a second symbol using a value that is based on a frequency domain representation of the distortion estimate and that is further based on a frequency domain representation of a quantized version of the updated estimate of the first symbol.

Abstract: Apparatuses and methods are disclosed for receiving or obtaining wireless signals. A first wireless device may receive a wireless signal including a first signal and a number of second signals. The first signal may contain data intended for the first wireless device, and the number of second signals may contain data intended for one or more second wireless devices. The first wireless device may select one or more of the number of second signals, determine a pre-whitening matrix based on an interference and noise covariance of the unselected second signals, and recover the first signal by using the pre-whitened signal.

Abstract: Systems and methods are disclosed for decoding wireless signals. For example, a wireless device may receive a wireless signal, de-interleave the received wireless signal to produce a first encoded signal and a second encoded signal, generate a first set of a priori log likelihood ratios (LLRs) by decoding and de-interleaving the first encoded signal, and recover a set of information bits from the received wireless signal based at least in part on the second encoded signal and the first set of a priori LLRs.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless communication device may receive multiple data streams from one or more users, associate the multiple data streams with different user groups, and identify modulation symbols for the users after reducing signal contribution from modulation symbols associated with different user groups. For example, the device may receive a signal including multiple spatial streams, partition the data streams into different user groups, and determine a set of sequences from channel characteristics associated with the respective user groups. The wireless communication device may then apply the sequences to the received signal and to values associated with the channel characteristics. Subsets of values may be selected following the application of the sequences, and from the subsets of values, the wireless communication device may identify the sets of modulation symbols associated with one or more of the user groups.