Systems and methods are directed to low cost and low power carrier frequency offset (CFO) estimation in a receiver. In-phase (I) and quadrature (Q) samples of a wireless signal are received by the receiver and a first phase and a second phase are extracted from the outputs of a first autocorrelator with a first time-lag and a second autocorrelator with a second time-lag. The extracted first and second phases are combined to generate an estimated CFO of high accuracy and wide estimation range.

In an embodiment, an apparatus includes a buffer to store incoming orthogonal frequency division multiplexed (OFDM) samples. This buffer is configured to output the OFDM samples according to a read pointer that can be adjusted by a sum value corresponding to a sum of a length of a symbol and a feedback value, to align the read pointer with the symbol. In addition, the apparatus further includes a feedback circuit coupled to the buffer to receive the output OFDM samples and generate the feedback value based at least in part on the output OFDM samples.

Various embodiments disclosed herein provide for a reciprocity based channel state information acquisition scheme for frequency division duplex wireless communications systems. By converting channel state information from a traditional frequency-time domain to a Delay-Doppler domain, the channel state information feedback overhead can be reduced since the multi-path of radio propagation is reciprocal in terms of each ray and each cluster of antenna elements. Since the surrounding objects create the same multipath fading for both uplink and downlink transmissions, modeling the channel state information in the Delay-Doppler domain, and adjusting the sign of the Doppler value (negative/positive) can account for the multipath characteristics in both uplink and downlink.

A terminal device registration method and a device, where the method includes sending upstream registration window information to a terminal device, where the upstream registration window information indicates a starting position of an upstream registration window to the terminal device, receiving an upstream access signal sent by the terminal device from the starting position of the upstream registration window, where the upstream access signal includes a correlation sequence symbol and at least one orthogonal frequency division multiplexing (OFDM) symbol following the correlation sequence symbol, the correlation sequence symbol is constituted by a first sequence that meets a preset condition, and the at least one OFDM symbol modulates access information by means of differential phase modulation in a frequency domain, and performing upstream ranging according to the starting position of the upstream registration window and the correlation sequence symbol.

In many wireless communication systems, there is a major problem with the coverage in indoor environments because of signal loss during signal penetration through walls and other structures. Femto cells or repeaters may be used to address the signal coverage issue for indoor environments. The cost of femto cells or repeaters may be high depending on its capabilities. Method and apparatus are disclosed for a Signal Enhancer with reduced complexity to enhance the signal for an OFDM based TDD wireless communication system. This may result in a lower cost solution for improving the coverage and the overall communication system performance.

Disclosed are a method for acquiring synchronization in a cable network, and a physical (PHY) transmitter and PHY receiver. The method for acquiring synchronization in a cable network according to an embodiment includes receiving, by a PHY receiver, a signal from a PHY transmitter, and acquiring, by the PHY receiver, channel synchronization when a symbol in which a channel preamble exists is detected from the received signal and a position of a frequency in which a channel subcarrier exists is detected from the detected symbol by performing a cross correlation operation on the received signal and the channel preamble.

This application presents a direct data recovery from subspaces or parameters subranges of a received OFDM signal preidentified as corresponding to specific data symbols, by applying adaptive inverse signal transformation (AIST) method for reversing both original data coding and deterministic and random distortions introduced by a transmission channel, wherein both reversals are achieved by the same conversion of the subspaces or parameter subranges into data transmitted originally in order to eliminate an intermediate recovery of signals or parameters transmitted originally within the received OFDM signal. The AIST includes using both amplitudes and gradients of amplitudes of OFDM tone signals.

Methods, systems, and devices for wireless communication are described. A base station may broadcast a synchronization signal using a narrowband portion of a bandwidth of a cell. The synchronization signal may include a sequence repeated over several symbol periods using a cover code to support power-efficient cell acquisition. A user equipment (UE) receiving the synchronization signal may determine frequency and timing information for a cell by performing a weighted combination and accumulation of low complexity autocorrelation and cross-correlation procedures on the synchronization signal. The reduced complexity correlation procedures may be enabled based on the use of the cover code and a base sequence. In some cases, the cross-correlation may be performed at multiple sampling rates. The use of the cover code within the synchronization signal may also support correlation procedures that use recursive or repeated updates, which may allow for further reduced computational complexity relative to other cell search procedures.

This application relates to a communication method and apparatus, and may be applied to the internet of vehicles, for example, V2X, LTE-V, and V2V, or may be used in fields such as intelligent driving and intelligent connected vehicles. A first resource is determined in a first resource set, and a jth synchronization signal block in N synchronization signal blocks is sent on a jth candidate resource in N candidate resources. The first resource set includes M groups, and an ith group in the M groups includes X candidate resources. M×X candidate resources included in the first resource set may be used to transmit a synchronization signal block. Each of the N synchronization signal blocks occupies Y symbols in time domain, where Y is an integer greater than or equal to 5. The first resource includes the N candidate resources, and the N candidate resources belong to one or more groups in the M groups.

A receiving device 100 includes a reception unit 10, a delay signal generation unit 22, a difference calculation unit 23 that calculates a phase difference between the received signal and the delay signal, a variance calculation unit 24 that calculates a variance of the phase difference within a plurality of calculation sections while sliding a set of the plurality of calculation sections which are set corresponding to a cyclic prefix group assigned to a predetermined symbol group included in the received signal, together on the time axis, a symbol detecting unit 25 that detects a position of a symbol in the symbol group on the time axis, based on the position of the minimum peak of the variance on the time axis, and a synchronization timing signal generation unit 29 that generates a synchronization timing signal, based on information on the position of the symbol on the time axis.