Various strategies and devices for same are disclosed to correct for/mitigate frequency offset (such as due to differing accuracies between an oscillator of a transmitting device and an oscillator of a receiving device) and Doppler shift (such as due to a changing relative position between a receiving device and a transmitting device). These strategies may be employed in a MIMO setting, such as, e.g. a stationary base station and a plurality of terminal devices (e.g. user devices, mobile stations, etc.), in which the transmissions for each terminal device may be associated with a different frequency offset and a different Doppler shift.

Systems and methods are provided for transmitting OFDM signals through a communication channel exhibiting frequency selective fading, such as an aeronautical 2-ray channel, using a signal modulation scheme at the transmitter that is selected based on a measurement of signal to distortion ratio (SDR) at the receiver. The SDR measurement at the receiver is used to generate an estimated best modulation scheme based on the real-time detection and measurement of SDR at the receiver, and provide feedback to the transmitter through a feedback channel of the newly selected modulation scheme. In certain configurations, the selected modulation scheme is one of multiple possible quadrature amplitude modulation (QAM) schemes, which enables adaptation of the transmitted OFDM signal to optimize throughput based on distortion of individual tones of the OFDM signal received at the receiver.

An operation method of a first apparatus configured to communicate with a second apparatus in a wireless local area network (WLAN) system including the first apparatus and the second apparatus includes receiving, from the second apparatus, a null data packet (NDP) based on a certain protocol standard, estimating a channel with the second apparatus on the basis of the NDP, determining, on the basis of the estimated channel, whether or not a channel smoothing-related condition is satisfied, generating channel smoothing-related phase information on the basis of a result of the determination, and transmitting, to the second apparatus, a feedback frame including the channel smoothing-related phase information.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication that tone reservation is to be applied to one or more subcarriers for one or more downlink communications. The UE may transmit one or more uplink signals, using the one or more subcarriers, for measurement by a base station. The UE may receive the one or more downlink communications having the tone reservation applied to the one or more subcarriers, the one or more subcarriers having tone reservation applied based at least in part on the measurement of the one or more uplink signals on the one or more subcarriers. Numerous other aspects are described.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may perform online spur detection and mitigation scheme. The UE may identify spurs during operation, in real time, and apply cancelation and noise equalization to address identified spurs. The UE may apply a high pass filter to reference signals. During a symbol, the UE may apply the high pass filter by estimating the channel on one or more neighbor tones (e.g., tones of higher frequency and tones of lower frequency that also carry reference symbols). Because the UE may assume that a channel will generally be smooth, and that noise may vary slowly or steadily across frequency resources, the UE may compare the channel noise of a particular tone to an average or normalized channel noise of the one or more neighbor tones.

The present disclosure relates to a method for operating a terminal and a base station in a wireless communication system and an apparatus for supporting the same. As an example of the present disclosure, a method for operating a terminal in a wireless communication system may include: processing data symbols so that a first unique word (UW) discretely located in a frequency domain does not overlap with the data symbols; and transmitting a first unique word (UW)-orthogonal frequency division multiplexing (OFDM) symbol that adds the data symbols, which are processed not to overlap, and the first UW discretely located in the frequency domain.

A method for reducing a memory requirement in an uplink receiver using a Sounding Reference Signal (SRS) channel along with a Demodulation Reference Signal (DMRS) for channel estimation in SC-FDMA/OFDM based radio access technologies is provided. The method includes (i) requesting the Sounding Reference Signal (SRS) and receiving the Sounding Reference Signal (SRS), by a base station, from at least one user device and performing corresponding channel estimation, (ii) scheduling, by the base station, at least one of a data or control channel transmission, and (iii) demodulating, using a SC-FDMA/OFDM demodulator, received SC-FDMA/OFDM symbols that corresponds to at least one of the data or control channel transmission scheduled by the base station and saving the demodulated SC-FDMA/OFDM symbols for one DMRS interval in a buffer until channel estimation is ready, thereby reducing the memory requirement of the uplink receiver.

The invention relates to a method for transmitting at least K reference signals in a radio signal to be transmitted over a wireless communication system, said radio signal being intended to be emitted by an emitter comprising at least a transmit antenna configured for emitting on a number M of subcarriers S.sub.1, . . . , S.sub.M amongst which at least a number K of different subcarriers S.sub.q+1, S.sub.q+2, . . . , S.sub.q+K are contiguous, the respective frequencies of the contiguous subcarriers S.sub.q+1, S.sub.q+2, . . . , S.sub.q+K being ordered, said radio signal being provided by: inserting the at least K reference signals P.sub.1, . . . , P.sub.K so that the at least K reference signals P.sub.1, . . . , P.sub.K are respectively transmitted on the K contiguous subcarriers S.sub.q+1, S.sub.q+2, . . . , S.sub.q+K; emitting the radio signal including the at least K reference signals.

A method and system for providing sub-band whitening are herein provided. According to one embodiment, a method estimating an interference whitening (IW) factor based on a legacy-long training field (LLTF) signal, updating the estimated IW factor during transmission of a data symbol, and scaling the data symbol based on the updated IW factor and the estimated IW factor.

A user client device with a single receive (RX) chain, a first antenna and a second antenna, and a processor that causes the user client device to couple the single RX chain to the first antenna to receive a first data packet on a first channel and determine a first channel state information (CSI) tile of the first channel based on one or more fields in the first data packet, decouple the first antenna from the single RX chain and couple the second antenna to the single RX chain to continue receiving the first data packet on a second channel, determine a second CSI tile of the second channel based on one or more of a portion of the first plurality of fields, aggregate the first CSI tile with the second CSI tile, and generate a CSI matrix based on aggregating the first CSI tile with the second CSI tile.