Devices and methods of transmit opportunity (TXOP) with continued listen-before-talk (LBT) are generally described. A user equipment (UE) can be configured to perform a single LBT during an LBT scanning instance, to detect availability of an unlicensed wireless channel. Upon detecting availability of the channel, data is encoded for transmission during a TXOP with a TXOP duration. A pause in the transmission of the data is initiated upon expiration of a first time interval of the TXOP. A continuous LBT procedure is performed upon expiration of the pause, to determine a plurality of sensing metrics indicating occupancy of the unlicensed wireless channel. The transmission of the data is resumed during the TXOP for a second time interval, when at least one sensing metric of the plurality of sensing metrics is below a threshold.

Disclosed are a method and an apparatus for estimating a frequency offset in a wireless communication system. The method for estimating a frequency offset of the present disclosure comprises the steps of: acquiring a first symbol from which a cyclic prefix (CP) symbol of a received symbol is removed; acquiring a second symbol from which data having a length corresponding to a length of CP is removed at an end opposite to the end in which the CP is present in the received symbol; and estimating the frequency offset by using the first symbol and the second symbol.

Provided are a method and device for determining a sequence group and a method and device for determining a cyclic shift. The method includes: determining a symbol index of a first specified orthogonal frequency division multiplexing (OFDM) symbol in a scheduling unit; and determining a sequence group or cyclic shift used by a channel or a signal according to the symbol index.

Half tone offset may be utilized to mitigate signal distortion caused by DC bias within OFDM-based systems. In addition a cyclic prefix may be utilized within an OFDM-based system to mitigate inter-symbol-interference. Presented herein are techniques and methods to efficiently apply a cyclic prefix to an OFDM symbol with a half tone offset.

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.

Half tone offset may be utilized to mitigate signal distortion caused by DC bias within OFDM-based systems. In addition a cyclic prefix may be utilized within an OFDM-based system to mitigate inter-symbol-interference. Presented herein are techniques and methods to efficiently apply a cyclic prefix to an OFDM symbol with half tone offset for low power systems.

Methods, systems, and devices for time domain single carrier (SC) waveform communications are described. A user equipment (UE) may generate an SC waveform by resampling (e.g., up-sampling) mapped information bits prior to insertion of a cyclic prefix (CP) or guard interval (GI). Performing resampling prior to CP/GI insertion allows for resource allocation flexibility and a base station may allocate resources for the SC waveform in accordance with this flexibility. For example, a base station may not be limited or restricted to a certain number of resources for SC waveform communications and may therefore determine a resource allocation for the UE based on the capability of the UE to perform resampling prior to CP/GI insertion. The resampling may be performed according to a set of parameters including a resampling ratio, which may be indicated to the UE via control signaling (e.g., from the base station).

A transmitter transmitting payload data using Orthogonal Frequency Division Multiplexed (OFDM) symbols, including: a frame builder configured to receive the payload data and to receive signalling data to use in detecting and recovering the payload data at a receiver, and to form the payload data with the signalling data into frames for transmission; a modulator configured to modulate a first OFDM symbol with the signalling data and to modulate one or more second OFDM symbols with the payload data; a signature sequence processor circuit providing a signature sequence; a combiner circuit combining the signature sequence with the first OFDM symbol; a prefixing circuit to prefixing a guard interval to the first OFDM symbol to form a preamble; and a transmission circuit transmitting the preamble and the one or more second OFDM symbols. The guard interval is formed from time domain samples of a part of the signature sequence.

The present invention relates to the technical field of communications, and specifically relates to an uplink transmission method, terminal, and base station, used for providing a pilot frequency transmission solution for a terminal supporting an CP-OFDM waveform, and comprising: a terminal determines a frequency domain starting position of a pilot frequency, the terminal being a terminal using CP-OFDM to perform uplink transmission; on the basis of a comb-type interval and the determined frequency domain starting position, mapping the pilot frequency onto a transmission pilot frequency symbol; and sending the pilot frequency mapped onto the symbol to a base station.

Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and a relevant device, characterized in that the method comprises: generating a cyclic prefix according to a partial time-domain main body signal truncated from a time-domain main body signal; generating a modulation signal based on a portion or the entirety of the partial time-domain main body signal; and generating time-domain symbols based on at least one of the cyclic prefix, the time-domain main body signal and the modulation signal, wherein the preamble symbol contains at least one of the time-domain symbols. Therefore, using the entirety or a portion of a certain length of a time-domain main body signal as a prefix, it is possible to implement coherent detection, which solves the issues of performance degradation with non-coherent detection and differential decoding failure under complex frequency selective fading channels; and generating a modulation signal as a postfix based on the entirety or a portion of the above truncated time-domain main body signal enables the generated preamble symbol to have sound fractional frequency offset estimation performance and timing synchronization performance.