In a digital communication system there is provided a method for OFDM channel estimation that jointly considers the effects of coarse timing error and multipath propagation. The method uses an iterative channel estimation technique, which considers the practical scenario of fractional timing error and non-sample space echo delays. The method does not require channel state information such as second-order statistic of the channel impulse responses or the noise power. Moreover, timing error can be conveniently obtained with the proposed technique. Simulation shows that, when comparing OFDM channel estimation techniques under DOCSIS 3.1 realistic channel conditions, the proposed algorithm significantly outperforms conventional methods.

A base station of a time reversal communication system is provided. The base station receives a set of channel probing signals from a set of terminal devices, determines channel impulse responses based on the channel probing signals, and determines location-specific signature waveforms based on the channel impulse responses, in which each of the location-specific signature waveforms is associated with a particular location of the respective terminal device. The base station generates a set of medium access layer parameters, in which each medium access layer parameter is associated with a particular one of the terminal devices. For each terminal device, the base station generates transmit data signals based on data intended for the terminal device, and the medium access layer parameter and the location-specific signature waveform associated with the terminal device. The base station transmits the transmit data signals wirelessly to the terminal devices.

The disclosure relates to a method performed in a network node for transmitting data in a wireless network. The network node is configurable for controlling a multiple input multiple output antenna system. The method comprises beamforming user specific data streams to one or more communication devices, UE.sub.1, . . . , UE.sub.K, wherein the beamforming is based on respective channel information available for each of the one or more communication devices, UE.sub.1, . . . , UE.sub.K, precoding control information streams using a transmit diversity scheme; and transmitting the beamformed user specific data streams and the precoded control information streams in a same transmission resource. The disclosure relates to a network node, method in communication device, communication device and computer programs and computer program products.

A channel transmission characteristic obtaining method and apparatus, where the method includes obtaining transmission characteristic curves of at least two channels in a cable modem in a channel scanning manner, where the at least two channels form one contiguous frequency band, and frequencies corresponding to the transmission characteristic curves of the at least two channels include frequency values on a same order of magnitude, and amplitude values on a same order of magnitude, translating the transmission characteristic curves of the channels in an amplitude direction, to make amplitudes corresponding to same frequencies on all transmission characteristic curves overlapped in order to form one continuous curve, and setting the continuous curve as a transmission characteristic curve of the contiguous frequency band.

A wireless communication device and method therein for time synchronization in a wireless communication network are disclosed. The wireless communication device determines a first timing (tc) by performing a coarse time synchronization based on a synchronization signal received by the wireless communication device, wherein the received synchronization signal is sampled either in an original sampling rate or a reduced sampling rate. The wireless communication device determines a second timing (tf) by performing a fine time synchronization based on the determined first timing (tc) and the received synchronization signal.

A system that incorporates the subject disclosure may include, for example, determining an interference based on a channel gain for each signal of a group of signals received at a receiver from a group of transmitters. A determination is made of an interference value based on a group of interference signals received at a receiver from a group of transmitters, wherein the interference value is based on channel gains that are estimated for the group of transmitters, and wherein a portion of the interference is self-interference generated from transmitting and receiving at a same time. One of an analog time domain cancellation, a digital time domain cancellation or both, is performed responsive to a determination that the interference value does not satisfy a threshold range of an analog-to-digital converter of the receiver. Other embodiments are disclosed.

Embodiments relate to apparatuses (10; 20), methods and computer programs for determining transmission control information. The Apparatus (10) is suitable for a base band unit (110) of a base station transceiver (100) of a mobile communication system (300), the base station transceiver (100) further comprising one or more radio units (120) configured to wirelessly communicate with the base band unit (110) using one or more wireless fronthaul links. The apparatus (10) comprises at least one output (12) configured to transmit a downlink component of the one or more wireless fronthaul links to the one or more radio units (120). The apparatus (10) further comprises at least one input (14) configured to receive an uplink component of the one or more wireless fronthaul links from the one or more radio units (120). The apparatus (10) further comprises a control module (16) configured to control the at least one output (12) and the at least one input (14). The control module (16) is further configured to transmit a reference signal via the at least one output (12) to the one or more radio units (120). The control module (16) is further configured to receive a loopback version of the reference signal via the at least one input (14) from the one or more radio units (120). The control module (16) is further configured to determine transmission control information based on an attenuation of the reference signal determined based on the loopback version of the reference signal. The transmission control information comprises information related to a per-radio unit transmission power to be used by the one or more radio units (120) for transmissions on the one or more wireless fronthaul links. The control module (16) is further configured to provide the transmission control information to the one or more radio units (120) via the at least one output (12).

A method of estimating a channel for mobile systems with insufficient cyclic prefix length, wherein the channel comprises a plurality of multipath components (,), includes: receiving a signal (y.sub.n) comprising a plurality of contributions of a transmit signal (x.sub.n[k], x.sub.n-1[k]) transmitted during a plurality of transmission time intervals (n, n1) on a plurality of sub-carriers of known pilots (kP.sub.b) and a plurality of sub-carriers of unknown data (k.Math.P.sub.b); determining an estimate of the plurality of multipath components (,) based on a probabilistic relation between the plurality of first contributions (x.sub.n[k], x.sub.n-1[k]) of the transmit signal, wherein the plurality of first contributions are transmitted during adjacent transmission time intervals (n, n1), and an observation of the received signal (y.sub.n[k]) at a subcarrier (kP.sub.b) of the known pilots, wherein the probabilistic relation is based on statistical properties of the plurality of first contributions (x.sub.n[k], x.sub.n-1[k]) of the transmit signal.

Methods and systems are described for communication channel prediction from received multipath communications in a wireless communications system. In one aspect, a baseband impairment compensation of at least one of sample frequency offset, carrier frequency offset, and time offset between a wireless transmitter and a wireless receiver is estimated. A plurality of complex value channel tap estimates is received for each of a plurality of channel taps. A plurality of complex value channel tap predictions is determined for a future multipath communication based on the prior received corresponding complex value channel tap estimates and the baseband impairment compensation.

This disclosure provides systems, methods and apparatuses for compensating for differences in path delays and phase offsets between receive paths of a wireless device. In one aspect, a device receives a first wireless signal using first and second receive paths, determines a first channel phase response of the first wireless signal as received by the first receive path, and determines a second channel phase response of the first wireless signal as received by the second receive path. The device compares the first and second channel phase responses with an expected channel phase response, and determines, for each of the first receive path and the second receive path, one or more phase correction values based on the comparison. The device adjusts the first and second channel phase responses based on the phase correction values.