One embodiment provides an apparatus. The apparatus includes an optimization module configured to determine a guard interval remainder based, at least in part on a comparison of an allowable microreflection interference level and an actual microreflection interference level; and a windowing module configured to window an OFDM (orthogonal frequency division multiplexed) symbol utilizing the guard interval remainder. The apparatus may further include a channel estimator module configured to determine a predicted channel frequency response based, at least in part, on a probing symbol; and a pre-equalizer module configured to pre-equalize the OFDM symbol based, at least in part, on the predicted channel frequency response.

Disclosed is a method for estimating dense multipath parameters by means of multipolarized broadband extended array responses, which includes: first transmitting multiple different transmitted signal sequences via a multipolarized antenna array, and processing received data in multiple snapshots according to the known transmitted signals, to obtain channel responses of multipolarized antenna components at all frequency points in a frequency band; extending the obtained channel response matrixes of multiple frequency points in multiple snapshots into a large two-dimensional channel response matrix; then, acquiring a delay parameter regarding multipath propagation by using a reference array element, and estimating two-dimensional departure and arrival angles by using a channel matrix subjected to frequency domain smoothing and dimensionality reduction; and afterwards, pairing the estimated departure and arrival angles, and estimating parameters such as the cross-polarization ratios, the initial phases, and the amplitudes of the sub-paths by using the estimated parameters.

Channel estimation with reduced overhead in a filter bank multi-carrier (FBMC) system is enabled by use of frequency-time blocks each comprising a pilot field with two pilot symbols and data symbols outside the pilot field. In embodiments, nearest neighbors of the pilot field are populated with data symbols which fulfill one or more symmetry relations enabling approximate interference cancellation. In a first embodiment, the pilot field consists of two frequency-consecutive and time-coinciding positions; the pilot field may be time-initial in a transmission or may be located in the interior of the transmission. In a second embodiment, a block comprises two frequency-coinciding and time-consecutive pilot symbols; the pilot field may be frequency-initial in a transmission or may be located in the interior of the transmission.

A method and device for detecting a signal of an LTE uplink system in an interference condition. The method comprises: receiving baseband signals of M receiving antennas, and after fast Fourier transform, conducting demapping to obtain frequency-domain baseband signals; extracting a DMRS inserted in a received signal of each antenna, and then, calculating a channel gain h.sub.l,k of each receiving antenna; combining the baseband signals and the channel gains of the M receiving antennas to obtain a signal matrix Y.sub.k and a gain matrix H.sub.k; calculating an interference noise covariance matrix R.sub.k on each subcarrier; conducting interference pre-processing on a received signal on each combined subcarrier to obtain the received signal (1) and the channel gain (2) after the interference pre-processing, where D=R.sub.k.sup.−1/2; and according to (3), conducting frequency-domain balancing on the received signal after the interference pre-processing.

Aspects of the disclosure relate to channel estimation and tracking in a wireless communication system. A wireless communication entity estimates a received signal utilizing any suitable process. The wireless communication entity applies a Wavelet decomposition filter to the estimated received signal to generate a channel coefficient estimate. The Wavelet decomposition filter may be configured to employ a Haar mother Wavelet. The wireless communication entity generates a prediction of a future channel estimate at a later time, by characterizing the channel according to a first-order autoregressive model of channel aging. Other aspects, embodiments, and features are also claimed and described.

Provided is a method for transmitting, by a user equipment (UE), a demodulation reference signal (DMRS) for a physical uplink shared channel (PUSCH) in a wireless communication system. A terminal receives a cyclic shift field, which indicates a first value and a second value, through a physical downlink control channel (PDCCH) from a base station, generates a first DMRS sequence and a second DMRS sequence, which are associated with a first layer and a second layer respectively, by using a first cyclic shift and a second cyclic shift, respectively, which are determined based on the first value and the second value respectively, and transmits the first DMRS sequence and the second DMRS sequence to the base station. Furthermore, the first value and the second value are separated by a maximum value corresponding to a total number of possible cyclic shifts.

Proposed are a method and a device for transmitting an NGV frame in a wireless LAN system. Specifically, a transmission device generates an NGV frame and transmits same via a first band. The NGV frame includes an L-STF, L-LTF, L-SIG, RL-SIG, NGV-SIG, NGV-STF, NGV-LTF and NGV-Data. The NGV-Data includes at least one midamble. The at least one midamble is generated on the basis of a sequence of the NGV-LTF. The sequence of the NGV-LTF includes two time sequences which, in a frequency domain, are mapped to a tone including two tone units, and in a time domain, are repeated in a single OFDM symbol. The at least one midamble includes one or two OFDM symbols.

The present invention provides a preamble sequence sending and receiving method and apparatus, and a system. The preamble sequence sending method includes: generating, by a transmit end, a frequency offset estimation sequence, where the frequency offset estimation sequence includes N subsequences each with a length of M, N is a positive integer greater than or equal to 2, and M is a positive integer; generating, by the transmit end, a prefix and a suffix based on the frequency offset estimation sequence; adding, by the transmit end, the prefix and the suffix before and after the frequency offset estimation sequence respectively to form a preamble sequence, where the prefix and the suffix are used for canceling multipath interference; and adding, by the transmit end, the preamble sequence to a data packet and sending the data packet to a receive end.

A communication apparatus 300 includes a first channel estimating unit 131 configured to perform a first channel estimation at a first frequency using a reference signal included in a signal sequence, a first weight information generating unit 133 configured to generate first weight information based on the first channel estimation, a synthesis processing unit 135 configured to perform weighted synthesis processing based on the first weight information, a second channel estimating unit 137 configured to perform a second channel estimation at a second frequency higher than the first frequency using a reference signal included in the signal sequence subjected to the weighted synthesis processing, a second weight information generating unit 139 configured to generate second weight information based on the second channel estimation, and a demodulation processing unit 141 configured to perform demodulation processing of the signal sequence subjected to the weighted synthesis processing based on the second weight information.

At least one crosstalk probing sequence out of a set of orthogonal crosstalk probing sequences is assigned to the at least one respective disturber line for modulation at the given carrier frequency of at least one respective sequence of crosstalk probing symbols, and error samples are successively measured by a receiver coupled to the victim line at the given carrier frequency while the at least one sequence of crosstalk probing symbols are being transmitted over the at least one respective disturber line are fed back for crosstalk estimation. The received error samples are next correlated with at least one unassigned crosstalk probing sequence out of the set of orthogonal crosstalk probing sequences for detection of a demapping error in the received error samples.