A method of receiving a signal by a receiver in a mobile communication system is provided. The method includes: receiving a reference signal from a transmitter; determining first channel information based on the received reference signal; receiving a data signal based on the first channel information; and determining second channel information based on the received data signal and the first channel information. Iterative channel estimation is performed to reduce channel estimation errors by determining errors of signals received from a turbo decoding unit and using symbol information as pilots even in subcarriers where the pilot signals are not transmitted, and to increase the accuracy of LLR calculation through an iteration process such as a detection and decoding process in comparison with the conventional technology, thereby increasing the reception performance of the turbo decoding unit and improving communication efficiency.

A method to compensate a carrier frequency offset (CFO) in a receiver is disclosed. The method includes receiving discrete time samples, obtaining a sample vector from the received discrete time samples, obtaining tentative CFO estimates based on the sample vector, selecting a CFO having a greatest compensation coefficient from the tentative CFO estimates, and compensating the CFO in the received discrete time samples.

Embodiments of this disclosure provide an apparatus and method for estimating a frequency offset, an apparatus and method for estimating a channel spacing and a system. The apparatus for estimating a frequency offset includes: a synchronization extracting unit configured to perform a training sequence synchronization extraction on a receiving sequence containing a periodic training sequence to obtain the training sequence; a delay correlation processing unit configured to parallelly perform autocorrelation operations of different delay amounts on the training sequence to obtain multiple parallel correlation sequences; a superimposition processing unit configured to perform a superimposition operation on the multiple parallel correlation sequences to obtain a single sequence; and a frequency offset estimating unit configured to determine a frequency offset according to a phase of a synchronization position of the single sequence in the training sequence. With the embodiments of this disclosure, anti-noise characteristic of the frequency offset estimation may be improved.

The present invention adopts a configuration such that when cooperative reception by a plurality of base stations is not applied, a reference signal sequence determined from a selection baseline value corresponding to the number of a sequence group allocated to a cell belonging to the device in question is selected from among a plurality of selection baseline values as a reference signal sequence for non-cooperative reception, whereas when cooperative reception by a plurality of base stations is applied, a reference signal sequence determined from one or more intermediate selection baseline values set between two adjacent selection baseline values corresponding to the number of a sequence group allocated individually to a terminal device is selected among the plurality of selection baseline values as a reference signal sequence for cooperative reception differing from the reference signal sequence for non-cooperative reception.

The present disclosure relates to a wireless communication apparatus capable of increasing throughput using MIMO in an LOS environment and a method for the same. A wireless communication apparatus based on the LOS-MIMO technique may comprise a multi-link configuration unit, a frequency response correction unit, a signal compensation unit, and a feedback unit. In the apparatus, an additional LOS-MIMO equalizer is used at the front of an LOS-MIMO estimator and a coding unit in order to compensate in-band frequency characteristics of frequency response characteristics estimated by the LOS-MIMO estimator and a signal channel estimator, whereby the LOS-MIMO estimation performance can be remarkably enhanced. Also, precise separation of multiplexed signals through the above-described LOS equalizer can make it possible to increase transmission capacity by using the LOS-MIMO which can be applied to high-order mode (e.g., over 16 quadrature amplitude modulation (QAM)) digital communications.

A device comprises a memory that stores instructions executed by one or more processors to obtain a plurality of received signals transmitted by a user equipment from a plurality of antenna elements in a cellular network. A plurality of complex channel values are calculated in an angle domain for a horizontal arrival angle and a vertical arrival angle per a received ray in a plurality of received rays in response to the plurality of received signals. A frequency-offset estimation is calculated and applied to the plurality of complex channel values. The plurality of offset complex channel values are transformed to a plurality of channel values in a time domain. A time-offset estimation is calculated and applied to the plurality of channel values. An expected value of the plurality of channel values is obtained to obtain a power angle delay profile for the geographical location of the user equipment.

Noise and interference may be estimated at a user equipment (UE) in a system that may support transmissions having different transmission time intervals (TTIs). The UE may perform a channel estimation for a first set of transmissions having a first TTI based at least in part on an estimated interference from a second set of transmissions having a second TTI that is shorter than the first TTI. The UE may perform channel estimation for orthogonal frequency division multiplexing (OFDM) symbols of the first set of transmissions. The first set of transmissions may then be demodulated based at least in part on the channel estimation for the first set of transmissions. Noise and interference may also be estimated based on one or more null tones within one or more OFDM symbols of the allocated resources.

A first communication device receives a plurality of training signal fields in a preamble of a data unit transmitted by a second communication device, the plurality of training signal fields in orthogonal frequency division multiplexing (OFDM) symbols comprising data and pilot tones. The first communication device determines first channel estimate data corresponding to the data tones in the OFDM symbols, and uses pilot tones in the plurality of training signal fields to track at least one of i) a phase offset and ii) a frequency offset while receiving the plurality of training signal fields to improve the first channel estimate data. The first communication device generates feedback data that i) includes data corresponding to the first channel estimate data, and ii) excludes data corresponding to second channel estimate data for the pilot tones in the plurality of training signal fields, and transmits the feedback data to the second communication device.

A representation method of channel state information for a receiving apparatus of a wireless communication system is disclosed. The channel state information includes a plurality of subcarrier data. The representation method of channel state information includes mapping each subcarrier data captured at a first timing onto planar component vectors; and respectively accumulating the planar component vectors corresponding to an identical direction of each subcarrier data captured at the first timing to generate a characteristic chart of channel state.

This application discloses a channel estimation method and apparatus. When time-domain channel estimation is performed on a first slot, the first slot and at least one second slot are first determined. The first slot and each second slot form continuous slots. Then, a first signal corresponding to the first slot and a second signal corresponding to each second slot are obtained, and a time-domain channel estimate for the first slot is determined based on the first signal and each second signal. In embodiments of this application, when a time-domain channel estimate for a specific slot is determined, time-domain channel estimation is performed by using time-domain correlation of channels in combination with signals of a plurality of slots, so as to obtain a more accurate channel estimation result, thereby improving baseband demodulation performance.