A precoding scheme to accommodate user equipment (UEs) having higher Doppler speeds. In such transmission schemes, a different precoding matrix is applied to each orthogonal frequency division multiplex (OFDM) symbol in the transmission stream. Additionally, a downlink control message format is defined to handle assignment of multiple different transmission schemes using the same message format. The downlink control message format includes a control element in one of the message fields along with a set of parameters specifically applicable to the assigned transmission scheme. Based on the value of this control element, the UE sets the specific transmission scheme and determines a set of interpretation rules uniquely associated with that transmission scheme. Using the interpretation rules, the UE is able to read the set of parameters as applied to the selected transmission scheme.

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.

A data detection method, having the steps of: a. receiving a signal transmitted over a communication channel, the signal being representative of at least a stream of interfering symbols x.sub.k, each representing one or more bits of a transmitted message; b. filtering the received signal through at least a filter bank having at least a first filter representative of a linear response of the channel and a second filter representative of a non-linear response of the channel, and sampling the filtered signals at the symbol rate, thus obtaining respective sequences of filtered samples r.sub.k.sup.(1) r.sub.k.sup.(3); and c. jointly computing the a posteriori probabilities of N>1 consecutive symbols x.sub.k. A data detector for carrying out such a method, and a method of transmitting data over a nonlinear channel, optimizing spectral efficiency when data detection is performed using such a method is also provided.

Embodiments of the present invention provide a method and a device for processing interference, wherein according to a first demodulation reference signal DMRS pilot symbol carried by a first subcarrier used by an uplink user equipment, an interference channel matrix of an uplink interference channel from the uplink user equipment to a D2D receiving end is measured, wherein the first subcarrier is a subcarrier shared by a D2D transmitting end and the uplink user equipment; a null space matrix of the uplink interference channel is calculated according to the interference channel matrix; and the signal received by the D2D receiving end via the first subcarrier is processed by using the null space matrix to eliminate an interference signal which comes from the uplink user equipment in the signal.

Channel estimation where at least two sets of multipath components for a reception range are formed by applying spatial filtering to reference signal information measured by a communication device. Each set of multipath components comprises a number of multipath components that is less than the number of multipath components for the range. Separate parameter estimations are performed on the at least two sets of multipath components. The communication device may be a mobile device, and measurements may be provided by the mobile device in multiple of locations.

Methods, systems, and computer program products for decoding a received data signal in a communication system by iteratively constructing a decoding tree, each node of said decoding tree corresponding to a component of a symbol of said data signal, and being associated with a metric, the construction of the decoding tree implementing at least one iteration of the following steps, for a current node of the tree stored in the top of a stack: generating (102) a reference child node of said current node from said vector representing the received data signal, from the reference child node, generating (106) a first neighbor child node by subtracting a positive integer parameter from the value of the reference node, and a second neighbor child node by adding said positive integer parameter to the value of the reference child node; storing (108) in said stack three child nodes deriving from the reference child node and from said first and second neighbor child nodes, each child node being stored in the stack in association with node information comprising a predetermined metric, the nodes in the stack being ordered by increasing values of metrics; removing (109) the current node from said stack; selecting (111) the top node of said stack as the new current node;
wherein said method further comprises determining an estimation of said data signal from the node information stored in said stack.

A method decodes an optical signal transmitted over an optical channel from a transmitter to a receiver. The receiver receives the transmitted optical signal to produce a digital signal which is filtered in the frequency domain for compensating static effects and/or dynamic effects. The filtering is performed in the frequency domain, while the frequency coefficients of the filter are updated in the time domain by updating at least some of time coefficients of the filter and transforming the time coefficients into the frequency domain.

A system, method and device for wireless communication is provided. The method includes receiving, by a receiver, data from a transmitter, storing the data in the receiver, and determining, by the receiver, a probability of a bit stored in the data and a probability of a symbol based on the probability of the bit, wherein determining the probability of the bit includes moving a decision boundary associated with a constellation diagram.

A 5G base station transmitter at least partially precodes data for beam forming, and generates digital precoded baseband signals. Cross product circuitry coupled to the digital precoder, generates digital cross products of the digital precoded baseband signals. Both the baseband signals and the cross products are put through digital-to-analog converters (DACs), then provided to an analog non-linear precoder. The analog non-linear precoder combines the analog baseband signals, the cross products, with pre-distortion and precoder coefficients to generate a signal that is pre-compensated for power amplifier non-linearity. The pre-compensated signal is amplified by the power amplifier and transmitted via a phased antenna array. The number of extra DACs required for inserting pre-distortion when a hybrid digital/analog precoder is used can be limited to approximately $\frac{N_{\mathrm{RF}}\left(N_{\mathrm{RF}}-1\right)}{2},$
where N.sub.RF is the number of outputs of the digital precoder. This is significantly fewer than the number of extra DACs used by other methods.

A method for predistortion comprising receiving a plurality of input signals forming a multiple-input signal in a multiple-input multiple-output system, generating a pre-distorted multiple-input signal from the received multiple-input signal, generating a multiple-output signal by feeding the pre-distorted multiple-input signal into a multiple-input and multiple-output transmitter, estimating impairments generated by the multiple-input and multiple-output transmitter, the impairments comprising nonlinear crosstalk between distinct ones of the plurality of input signals; and adjusting the pre-distorted multiple-input signal to compensate for the estimated impairments.