Techniques and architectures for multi-stage cancellation of self-interference (SI) and joint cancellation of mutual-interference (MI) and residual SI in signals received by devices of a full-duplex multi-cell network are disclosed. In various examples, channel estimations and interference cancellation operations are performed utilizing multiple orthogonal training signals transmitted by network devices during a common over-the-air training period. Training signals derived from the orthogonal training signals during transmission are utilized to generate SI estimation information and perform at least a first SI cancellation operation on a received signal that includes at least first and second orthogonal training signals. The received signal and orthogonal training signals are then used to estimate a MI channel impulse response and a (residual) SI channel impulse response for use in joint MI/SI cancellation operations on further received signals. Details regarding the design of the orthogonal training signals and a unique system-level delay calibration procedure are also provided.

This document discloses a solution for performing interference cancellation in a radio receiver. According to an aspect, there is provided a method for an apparatus of an access node, comprising: receiving, by the apparatus from a first radio unit of the access node via a first interface, a first spectrally whitened channel parameter and a first spectrally whitened data stream; receiving, by the apparatus from a second radio unit of the access node via a second interface, a second spectrally whitened channel parameter and a second spectrally whitened data stream; summing, by the apparatus, the first spectrally whitened channel parameter with the second spectrally whitened channel parameter and summing the first spectrally whitened data stream with the second spectrally whitened data stream; and extracting, by the apparatus, a desired data stream from the summed spectrally whitened data streams by using the sum of the first spectrally whitened channel parameter and the second spectrally whitened channel parameter.

Characteristics of channels from an antenna array to a transceiver are characterized based on reciprocity in an approach that eliminates a need for channel feedback from the transceiver. In some embodiments, these channel characteristics are used in MIMO communication to a plurality of transceivers from the antenna array.

A method and apparatus are provided for reducing the number of pilot symbols within a MIMO-OFDM communication system, and for improving channel estimation within such a system. For each transmitting antenna in an OFDM transmitter, pilot symbols are encoded so as to be unique to the transmitting antenna. The encoded pilot symbols are then inserted into an OFDM frame to form a diamond lattice, the diamond lattices for the different transmitting antennae using the same frequencies but being offset from each other by a single symbol in the time domain. At the OFDM receiver, a channel response is estimated for a symbol central to each diamond of the diamond lattice using a two-dimensional interpolation. The estimated channel responses are smoothed in the frequency domain. The channel responses of remaining symbols are then estimated by interpolation in the frequency domain.

The embodiments herein use a factorization based technique for determining filter coefficients for a subset of the subcarriers in a wireless frequency band. Once the filter coefficients for the subset of the subcarriers are calculated, the network device uses these filter coefficients to identify the filter coefficients in a neighboring subcarrier. To do so, the network device uses pseudo-inverse iteration to convert the already calculated filter coefficients into filter coefficients for a neighboring subcarrier. The network device can repeat this process for the next set of neighboring subcarriers until all the filter coefficients have been calculated.

A multi-antenna network system has a reduced operational complexity for matrix inversion by referring to the variations of the status of a plurality of communication channels at a first time duration and a second time duration. Therefore, the speed for calculating matrix inversion is improved. Accordingly, the amount of servo antennas and/or user antennas operating in the same multi-antenna network system can be increased.

An adaptive filter circuit includes a plurality of filter cores associated with each other and configured to perform a calculation operation on a first target input signal, and an auxiliary core configured to generate cross-terms between block correlation matrices respectively corresponding to kernels that correspond to the first target input signal and provide the cross-terms to the plurality of filter cores, where the plurality of filter cores are further configured to estimate effective channels respectively corresponding to the kernels based on the cross-terms.

Techniques and architectures for multi-stage cancellation of self-interference (SI) and joint cancellation of mutual-interference (MI) and residual SI in signals received by devices of a full-duplex multi-cell network are disclosed. In various examples, channel estimations and interference cancellation operations are performed utilizing multiple orthogonal training signals transmitted by network devices during a common over-the-air training period. Training signals derived from the orthogonal training signals during transmission are utilized to generate SI estimation information and perform at least a first SI cancellation operation on a received signal that includes at least first and second orthogonal training signals. The received signal and orthogonal training signals are then used to estimate a MI channel impulse response and a (residual) SI channel impulse response for use in joint MI/SI cancellation operations on further received signals. Details regarding the design of the orthogonal training signals and a unique system-level delay calibration procedure are also provided.

A network device generates a successive joint channel estimation based on interference cancellation processes to eliminate or reduce colliding interferences (colliders) at a receiver end. A selection component selects a strongest interference collider from among pseudo noise sequences operating as colliders. A 2 by 2 matrix successive joint channel estimation component performs a successive 2 by 2 matrix joint channel estimation with an initial correlation metric between the strongest interference collider and each remaining interference collider in a first iteration of a set of iterations. A correlation metric component generates an updated correlation metric vector based on the 2 by 2 matrix joint channel estimation. Another 2 by 2 matrix joint channel estimation is then performed with the updated correlation metric vector between a next strongest interference collider and remaining interference colliders of the plurality of interference colliders at a second iteration of the set of iterations.

A transmission apparatus including the number of antennas different from a reception apparatus and performing transmission by SC-MIMO to and from the reception apparatus includes a training signal generation unit that generates a known signal predetermined, a CP addition unit that adds a CP to each symbol of a transmission signal including the known signal, a weight generation unit that generates a transmission weight based on a transposed adjugate matrix that is a product of a channel matrix estimated based on the known signal by the reception apparatus and a complex conjugate transpose of the channel matrix, and a transmission beam formation unit that uses the transmission weight to form a transmission beam for the transmission signal where the CP is added.