Systems and methods for a non-data-aided (NDA) approach to advanced OFDM timing are provided. This approach allows for accurate OFDM symbol timing and synchronization by avoiding inter-symbol interference (ISI) in multipath environments where an earliest arriving signal may not be the strongest signal. The NDA approach may rely on generating and applying a bias correction to a combined correlation result of the multi-path signals.

There is provided mechanisms for transmission of reference signal resources from a terminal device. A method is performed by the terminal device. The terminal device comprises at least two antenna panels and a baseband chain operable to be switched between the at least two antenna panels. The baseband chain is thereby connected to each of the antenna panels one at a time. The method comprises distributing a fixed set of reference signal resources among the at least two antenna panels by selecting which beams are to be used for transmission of the reference signal resources. The reference signal resources are distributed among the at least two antenna panels according to antenna panel selection information. The method comprises transmitting each of the reference signal resources in a respective one of the beams as the baseband chain is connected to each antenna panel used for generating the beams.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive an indication of a subcarrier spacing (SCS) for communications in a transmission time interval (TTI), such as a half-subframe, including multiple symbols, corresponding cyclic prefixes, and a padding duration which is at least as long as a symbol duration. The UE may receive a configuration for the padding duration, indicating that at least a portion of the padding duration is reallocated for a reference signal that indicates waveform parameters for one or more symbols of the TTI after the padding duration. The UE may receive the reference signal indicating the waveform parameters during the portion of the padding duration and communicate during the one or more symbols of the TTI according to the waveform parameters.

In an 802.11az wireless system, a first station device transmits an NDP PPDU data unit in accordance with a range measurement packet exchange by constructing the NDP PPDU data unit to include an uplink (UL) length field element or a legacy signal length (LLEN) field element derived from a specified number of symbols (N.sub.HE-LTF) and number of repetitions (N.sub.LTF-REP) for the NDP PPDU data unit, and then sending the NDP PPDU data unit to a second STA device, where the values of the UL-length and LLEN field elements are computed as UL-Length=LLEN=10+y+6*Σ.sub.i=1.sup.NUM_USERS((N.sub.LTF-REP(i)+1)*N.sub.HE-LTF(i)), where y=0 for NTB I2R/R2I NDP and TB R2I NDP PPDUs, and where y=3 for TB-I2R NDP PPDUs.

The guard-space reference disclosed herein is a signal transmitted in the guard spaces separating message data intervals, and configured to reveal amplitude noise or phase noise or both, using 5G or 6G technology. For example, the transmitter can transmit an I-branch with a predetermined amplitude level, and an orthogonal Q branch with zero amplitude, in the guard space. The receiver can measure the received amplitude and phase of the guard-space reference, subtract the initial amplitude and phase, and thereby measure both phase noise and amplitude noise. The receiver can then subtract the measured amplitude and phase effects from the message data, thereby negating both phase noise and amplitude noise. Guard-space references disclosed herein can preserve the inter-subcarrier orthogonality, inter-symbol separation, and signal circularity advantages of prior art, while additionally providing both amplitude noise and phase noise mitigation. Examples are suitable for wireless standards.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) or a base station may generate a discrete Fourier transform (DFT) waveform from separate DFT inputs of data content, a guard interval (GI) sequence, and tail suppression samples. The UE or the base station may generate a first communication with the DFT waveform using an inverse fast Fourier transform (IFFT) operation. The first communication may include, in a time domain, a data signal corresponding to the data content and a GI-based tail signal that corresponds to the GI sequence and that is suppressed with a tail suppression signal based at least in part on the tail suppression samples. The UE or the base station may transmit the first communication. Numerous other aspects are described.

A method and apparatus are disclosed from the perspective of a first network node served by a second network node. In one embodiment, the method includes the first network node performs a transmission to the second network node with a timing advance, wherein the timing advance is set to transmission delay between the first network node and the second network node or is set to the transmission delay with a timing reduction.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify a gap period following a downlink portion of a time division duplexing (TDD) frame. The UE may selectively perform, based at least in part on the gap period, a clear channel assessment (CCA) on a channel of a radio frequency spectrum band. The UE may transmit at least one of a sounding reference signal (SRS) or a physical random access channel (PRACH) preamble in a set of initial symbols of an uplink portion of the TDD frame following the gap period, wherein the SRS or PRACH preamble is frequency-domain multiplexed during the set of initial symbols with one or more of: a demodulation reference signal (DMRS), an uplink data transmission, an uplink control transmission, or a random access transmission.

The present specification relates to a reception apparatus and method for demodulating a signal in a wireless AV system. The reception apparatus estimates a transmission signal on the basis of an MMSE weight matrix. The reception apparatus divides the estimated transmission signal for respective reception antennas and performs an IFFT. The reception apparatus estimates and compensates for phase noise for the respective reception antennas on the basis of the signal for which the IFFT has been performed. The reception apparatus demodulates the estimated and compensated signal for respective streams.

A base station is configured to determine a sounding reference signal (SRS) configuration that has a plurality of cyclic shifts for a comb 8 SRS, a plurality of user equipment (UE) ports for transmitting the comb 8 SRS and a mapping of the plurality of cyclic shifts to the plurality of UE ports. The base station is further configured to transmit the SRS configuration to the UE.