Methods, systems, and devices for wireless communications are described. A user equipment (UE) may communicate with a base station by initiating a random access procedure with a two-root preamble. The UE may receive, from the base station, control signaling that indicates a set of root preamble sequences. The UE may transmit, to the base station, a preamble signal that is generated based on a first root preamble sequence and a second root preamble sequence of the set of root preamble sequences. The UE may then monitor for a preamble response based on the preamble signal. In some cases, the base station may be a base station in a terrestrial network. In other cases, the base station may be a satellite in a non-terrestrial network (NTN).

Communication systems and methods in accordance with various embodiments of the invention utilize modulation on zeros. Carrier frequency offsets (CFO) can result in an unknown rotation of all zeros of a received signal's z-transform. Therefore, a binary MOCZ scheme (BMOCZ) can be utilized in which the modulated binary data is encoded using a cycling register code (e.g. CPC or ACPC), enabling receivers to determine cyclic shifts in the BMOCZ symbol resulting from a CFO. Receivers in accordance with several embodiments of the invention include decoders capable of decoding information bits from received discrete-time baseband signals by: estimating a timing offset for the received signal; determining a plurality of zeros of a z-transform of the received symbol; identifying zeros from. the plurality of zeros that encode received bits by correcting fractional rotations resulting from the CFO; and decoding information bits based upon the received bits using a cycling register code.

The disclosure provides a method and system to recover some or all of the data missing in types of gaps that occur in data streams received via telemetry. The gaps can be filled in real time to enhance operator understanding of current operations. For gaps created by special sequences sent via telemetry during a time interval that telemetry would be sending measurement blocks (MB) of data, the gaps can be filled using special MBs combined with MBs for a next time interval to create combined MBs, sent via telemetry, and extracted to backfill the gaps. For gaps caused by corrupted data, the gaps can be filled with data from overlapping MBs having overlapping data based on overlapping time intervals. For gaps caused by gap events, including different drilling rates of penetration, event MBs with sampling rates different than a predetermined sampling rate can be sent via telemetry.

A method for estimating a time of arrival of a signal transmitted over a wireless channel, includes receiving the signal by a receiving device to produce a received signal; filtering by a filter either the received signal or a code sequence, wherein the filter is designed to produce a correlation output that is near causal; correlating the received signal with the code sequence to create the correlation output that is near causal; wherein near causal means that early side lobes and an early part of a main lobe of the correlation output are sufficiently suppressed in order to substantially reduce an impact of delayed multipath onto a first path component in the received signal, wherein the first path is in an operating region; identifying in the correlation output, an observation window associated with a main lobe in the correlation output; processing the observation window to determine a time of arrival of the first path component in the received signal.

Systems and methods for indicating and determining channel structure information in a wireless communication network are disclosed herein. In one embodiment, a method performed by a first node is disclosed. The method comprises: receiving a wireless signal from a second node; obtaining channel structure information indicated by the wireless signal; determining a first waveform parameter set configured for the channel structure information indicated by the wireless signal; and determining transmission attributes of a transmission link between the first node and the second node in a predetermined time duration with respect to the first waveform parameter set based on the channel structure information.

The disclosure provides a method and system to recover some or all of the data missing in types of gaps that occur in data streams received via telemetry. The gaps can be filled in real time to enhance operator understanding of current operations. For gaps created by special sequences sent via telemetry during a time interval that telemetry would be sending measurement blocks (MB) of data, the gaps can be filled using special MBs combined with MBs for a next time interval to create combined MBs, sent via telemetry, and extracted to backfill the gaps. For gaps caused by corrupted data, the gaps can be filled with data from overlapping MBs having overlapping data based on overlapping time intervals. For gaps caused by gap events, including different drilling rates of penetration, event MBs with sampling rates different than a predetermined sampling rate can be sent via telemetry.

A method includes calculating first correlation values corresponding to a first symbol duration based on input samples, the input samples being generated from a received signal; calculating phase differences respectively corresponding to the input samples based on the first correlation values and second correlation values corresponding to a second symbol duration preceding the first symbol duration; updating accumulative phase differences respectively corresponding to the input samples based on the phase differences; and detecting a symbol boundary based on the updated accumulative phase differences.

The scheduling flexibility of CSI reference signals enables time and frequency synchronization using multiple non-zero CSI-RSs transmitted in the same subframe, or using CSI-RSs transmitted in the same subframe with other synchronization signals. Also, multiple synchronization signals may be scheduled in the same subframe to enable fine time and frequency synchronization without cell-specific reference signals.

Joint estimation of the framer index and the frequency offset in an optical communication system are described among various other features. A transmitter can transmit data frames using pilot and framer symbols. A receiver can estimate the framer index and frequency offset using the pilot and framer symbols, and identify the beginning of a header portion of a data frame. By identifying the beginning of the header portion of a data frame, the receiver can synchronize, with less error, the data transmitted by the transmitter and the data it received. To further improve the framer index estimation, a lock indicator signal can be generated to signal to other receiver components that the estimated framer indices are reliable. The receiver can determine frequency offset and additional framer index estimations with increased reliability when performed after the lock indicator signal is generated.

Aspects described herein relate to receiving, from a first node, a first symbol, and receiving, from a second node, a second symbol in accordance with a reception configuration, wherein the reception configuration includes at least one of a first gap period before the second symbol or a second gap period after the second symbol. Other aspects relate to transmitting the first symbol and the second symbol.