A receiver performing a half cyclic prefix (CP) shift on received subframes is disclosed, comprising: an analog to digital conversion (ADC) module; a cyclic prefix (CP) removal module coupled to the ADC module configured to retain a portion of cyclic prefix samples; a fast Fourier transform (FFT) module configured to receive samples from the cyclic prefix removal module, and to perform a FFT procedure on the received samples using a FFT window, the FFT window being shifted ahead based on the retained portion of cyclic prefix samples, to output an orthogonal frequency division multiplexed (OFDM) symbol; and a rotation compensation module coupled to the FFT module, the rotation compensation module configured to perform phase de-rotation of the OFDM symbol.

Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and relevant device. The generated preamble symbol contains: a time-domain symbol with a first three-segment structure; or a time-domain symbol with a second three-segment structure; or a free combination of several time-domain symbols with the first three-segment structure and/or several time-domain symbols with the second three-segment structure arranged in any order. Using the entirety or a portion of a certain length of a time-domain main body signal as a prefix, it is possible to perform 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 postfix or hyper prefix based on the truncation of the entirety or a portion of the time-domain main body signal would enable the generated preamble symbol to have sound fractional frequency offset estimation performance and timing synchronization performance.

Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and relevant device. The generated preamble symbol contains: a time-domain symbol with a first three-segment structure; or a time-domain symbol with a second three-segment structure; or a free combination of several time-domain symbols with the first three-segment structure and/or several time-domain symbols with the second three-segment structure arranged in any order. Using the entirety or a portion of a certain length of a time-domain main body signal as a prefix, it is possible to perform 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 postfix or hyper prefix based on the truncation of the entirety or a portion of the time-domain main body signal would enable the generated preamble symbol to have sound fractional frequency offset estimation performance and timing synchronization performance.

Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and relevant device. The generated preamble symbol contains: a time-domain symbol with a first three-segment structure; or a time-domain symbol with a second three-segment structure; or a free combination of several time-domain symbols with the first three-segment structure and/or several time-domain symbols with the second three-segment structure arranged in any order. Using the entirety or a portion of a certain length of a time-domain main body signal as a prefix, it is possible to perform 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 postfix or hyper prefix based on the truncation of the entirety or a portion of the time-domain main body signal would enable the generated preamble symbol to have sound fractional frequency offset estimation performance and timing synchronization performance.

Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and relevant device. The generated preamble symbol contains: a time-domain symbol with a first three-segment structure; or a time-domain symbol with a second three-segment structure; or a free combination of several time-domain symbols with the first three-segment structure and/or several time-domain symbols with the second three-segment structure arranged in any order. Using the entirety or a portion of a certain length of a time-domain main body signal as a prefix, it is possible to perform 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 postfix or hyper prefix based on the truncation of the entirety or a portion of the time-domain main body signal would enable the generated preamble symbol to have sound fractional frequency offset estimation performance and timing synchronization performance.

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).

Examples described herein include systems and methods which include wireless devices and systems with examples of cross correlation including symbols indicative of radio frequency (RF) energy. An electronic device including a statistic calculator may be configured to calculate a statistic including the cross-correlation of the symbols. The electronic device may include a comparator configured to provide a signal indicative of a presence or absence of a wireless communication signal in the particular portion of the wireless spectrum based on a comparison of the statistic with a threshold. A decoder/precoder may be configured to receive the signal indicative of the presence or absence of the wireless communication signal and to decode the symbols responsive to a signal indicative of the presence of the wireless communication signal. Examples of systems and methods described herein may facilitate the processing of data for wireless communications in a power-efficient and time-efficient manner.

A transmitter transmits payload data using Orthogonal Frequency Division Multiplexed (OFDM) symbols. The transmitter comprises a frame builder configured to receive the payload data to be transmitted and to receive first signalling data for use in detecting and recovering the payload data at a receiver, and to form the payload data and the first signalling data into frames for transmission, the first signalling data forming a part of the frames with the payload data. A modulator is configured to modulate a first OFDM symbol with the first signalling data and to modulate one or more second OFDM symbols with the payload data. A signature sequence processor provides a signature sequence, a combiner combines the signature sequence with the first OFDM symbol, and a transmission unit transmits the first and second OFDM symbols. The signature sequence provided by the signature sequence processor comprises at least one of a first synchronisation sequence or a second message sequence, the first synchronisation sequence and/or the second message sequence being combined by the combiner with the first OFDM symbol. The first synchronisation sequence is provided for a receiver to detect and to recover the first signalling data from the first OFDM symbol and the second message sequence provides message information to the receiver. The message information may be used to convey a specific message to a user such as an emergency warning relating to a natural disaster such as an earthquake or a tsunami warning.

A method for transmitting a random access preamble in a narrowband-IoT system supporting time division duplexing and an apparatus therefor. In some implementations, a method for transmitting a narrowband physical random access channel (NPRACH) preamble by a user equipment in a narrowband-Internet of things (NB-IoT) system supporting time division duplexing may include: receiving, from a base station, configuration information related to an uplink-downlink configuration; and transmitting, to the base station, the NPRACH preamble configured by considering the uplink-downlink configuration.

Determining timing of an OFDM signal comprises performing (610) an auto-correlation with a received signal, using a delay chosen to correspond to the duration of an OFDM symbol excluding the cyclic prefix, with the number of terms used in the summation in the correlation is at least as large as the smallest number of samples in any cyclic prefix of a subframe. Based on the auto-correlation, first and second correlation peaks meeting one or more predetermined detection criteria are detected (620), and evaluated to determine (630) that they are separated in time by an interval corresponding to an OFDM symbol interval. The method further comprises identifying (640), based on the two correlation peaks, one of the correlation peaks as corresponding to an OFDM symbol having a larger cyclic prefix than an adjacent OFDM symbol, and determining (650) a subframe and/or slot timing for the received signal, based on said identifying.