96 results about "Residual interference" patented technology

An impluse response h_mn(q) of each transmission path is estimated from N received signals r_m (m=1, . . . , M) and a known signal (for a number of users equal to N, n=1, . . . , N). M×N matrix H (q) having h_mn(q) as an element and a Q×Q matrix H having H(q) as an element are determined (where Q represents a number of multipaths of each transmitted wave and q=0, . . . , Q−1). A soft decision value b′_n(k) is determined from decoded λ₂ [b_n(k)], and this is used to generate an interference component matrix B′(k) to generate an interference replica H·B′(k). The interference replica H·B′(k) is subtracted from a received matrix y(k) to determine y′(k). y(k) and H are used to determine an adaptive filter coefficient w_n(k) to be applied to an n-th user in order to eliminate residual interference components in y′(k) according to the minimum mean square error criteria. y(k) is passed through w_n(k) to provide a log-likelihood ratio as a received signal from the user n from which interferences are eliminated.

A radio receiver (100) has an equalizer (500) that operates in the time domain to remove residual interference that is not removed by an IF filter (200) operating in the frequency domain that is caused by an adjacent interfering FM station. The equalizer (500) includes a modified constant modulus algorithm (CMA) to generate a tap update signal from the output of the equalizer (500). The equalizer (500) uses the modified CMA to reduce an amplitude fluctuation of the received signal caused by the adjacent interfering station. The CMA is modified to use an infinite impulse response (IIR) filter (540) to generate the tap update. The IIR filter (540) also speeds up a convergence of the modified CMA to provide better performance.

There is provided a micro integrated wireless repeater apparatus for canceling an interference signal, including: a receiving means for receiving a repetition signal; an analog interference cancellation means for generating an interference cancellation signal according to a control signal and removing an interference signal from the repetition signal received from the receiving means; a digital interference cancellation means for canceling a residual interference signal remaining in a repetition signal obtained by canceling an interference signal component by the analog interference cancellation means; a control means for controlling the analog interference cancellation means by transmitting the control signal to the analog interference cancellation means according to control information received from the digital interference cancellation means; and a transmitting means for transmitting a repetition signal obtained by canceling a residual interference signal component by the digital interference cancellation means.

The present disclosure provides methods and apparatuses for demodulating discrete-time desired signals in a period-T_d bandpass desired signal in the presence of interference that results from a period-T bandpass interference signal that has been nonlinear distorted. Estimation of the nonlinear-distorted interference and subsequent cancellation from a received signal, that includes the interference and desired signal, produces residual-interference signals. The demodulation of the residual-interference signals uses an equalization technique when T_d is not equal to T. The estimation, cancellation, and demodulation are adapted for changing nonlinear distortion effects.

The invention provides a self-adapting interference cancellation device adopting a technical scheme of two-stage cancellation, namely the interference margin of the first-stage cancellation is used as the interference input of the second-stage cancellation to perform interference cancellation twice, which is the theory of two-stage interference cancellation. Therefore, the residual interference signal components can be further reduced. Two-stage interference cancellation is performed in sequence, namely the second-stage interference cancellation process is performed after the first-stage interference cancellation process is finished, and the second-stage programmable attenuator is in a full attenuation state in the first-stage interference cancellation process. The self-adapting interference cancellation device is mainly applied to elimination of coupling interference among co-location dual-mode antennae, and inhibits the coupling interference among co-site dual-mode antennae without reducing the spectrum resource utilization rate.

Several subscriber signals are transmitted simultaneously and at the same frequency by a central transmitter to several decentralized receivers which do not cooperate with each other, by digital message transmission in a broadcast channel. A common transmission signal, which enables an error-free individual reception, should be generated with knowledge of all subscriber signals and of the current transmission conditions, by signal preprocessing methods on the transmission side. Known nonlinear precoding methods totally suppress the interference signals, so that the channel diversity cannot be used. In the claimed precoding method, the occurring interference signals are, on the contrary, taken into account. On the basis of a modulo arithmetic calculation, the transmission channel is not totally equalized, but virtually divided, so that the transmission of the subscriber signals is continued periodically; the signals are selected according to the minimal transmission power and pre-equalized, in a linear manner, and the residual interferences, still remaining between the subscriber signals, may assume special values from a preset set of values. The set of values is selected, so that the interference signals of the other subscribers are also merely reflected in the otherwise already existing periodic continuation and can be suppressed or used as required by a modulo decision, on the reception side.

The invention belongs to the field of image processing, and discloses a space-time correlated channel massive MIMO transmission method. According to the space-time correlated channel massive MIMO transmission method, a time-shifted pilot frequency system structure is adopted, a user selection scheme based on the position of a user is utilized, user sub-groups having large interference in surrounding cells are omitted, so that data interference of the adjacent cells is reduced in a channel estimation stage, meanwhile, interference among the cells is reduced in a downlink data transmission stage, and system capacity is promoted. On the basis of the user selection scheme, a Kalman estimation method is adopted, a space-time correlation between channels is used, residual interference among the cells is eliminated further, and channel estimation accuracy is promoted. By means of combination of a user selection process and Kalman channel estimation, more accurate channel estimation results are obtained under the space-time correlated channel of a multi-cell massive MIMO system, interference among the cells in a pilot frequency estimation stage is restrained, and meanwhile the throughput rate of downlink data of the system is increased.

Systems and methods which provide mitigation of self-interference in spectrally efficient full duplex (e.g., transmit and receive using the same frequency simultaneously) communications are described. Embodiments provide an interference mitigation structure having a multi-tap vector modulator interference cancellation circuit operable to cancel time varying multipath interference in the analog RF domain. A multi-tap vector modulator interference cancellation circuit of embodiments may comprise part of a multi-stage interference cancellation circuit, such as a multi-stage interference cancellation circuit comprising a multi-tap vector modulator interference cancellation circuit and a digital residual interference cancellation circuit. A digital residual interference cancellation circuit of embodiments provides residual interference cancellation. A multi-stage interference cancellation circuit configuration of embodiments is operable to provide cancellation of strong multipath signals as well as cancellation of residual multipath signals, including interference in the received signal associated with circulator leakage, antenna reflection and multipath.

It is possible to improve the CQI reception performance even when a delay is caused in a propagation path, a transmission timing error is caused, or a residual interference is generated between cyclic shift amounts of different ZC sequences. For the second symbol and the sixth symbol of the ACK/NACK signal which are multiplexed by RS of CQI, (+, +) or (−, −) is applied to a partial sequence of the Walsh sequence. For RS of CQI transmitted from a mobile station, + is added as an RS phase of the second symbol and − is added as an RS phase of the sixth symbol. A base station (100) receives multiplexed signals of ACK/NACK signals and CQI signals transmitted from a plurality of mobile stations. An RS synthesis unit (119) performs synthesis by aligning the RS phase of CQI.

The invention provides a method for estimating and compensating a lever arm effect in the case of a shaken base by a strapdown inertial navigation system, which is used for estimating the influence of the lever arm effect to the system and compensating according to a certain strategy, so that the precision of fine alignment and navigation calculation can be improved. The method comprises the following steps of: firstly, on the basis of coarse alignment, dividing a fine alignment process into two stages, wherein at a first stage: running a parameter identification method fine alignment algorithm of lever arm speed real-time compensating and spreading variable quantity, to estimate the residual interference speed except the lever arm speed in the system, and at a second stage: carrying out primary compensation on the residual interference speed; continuously running the parameter identification method fine alignment algorithm of the lever arm speed real-time compensating and spreading variable quantity, to estimate the misalignment angle information; and further modifying a coarse alignment result by the estimated misalignment angle, and confirming an initial pose matrix, so that the fine alignment can be completed. In the stage of navigation calculation, the lever arm speed is compensated in real time, a strapdown calculating program is operated, and a navigation result is provided.

The invention discloses a cooperative multi-point transmission method based on interference alignment and interference neutralization. The cooperative multi-point transmission method based on interference alignment and interference neutralization only uses base station side cooperation, eliminates residual interference and recovers expectation data through the precode vector design based on interference alignment and interference neutralization and an orthogonal projection filtering wave receiving technology adopted at a user side. Compared with the prior art, concurrent transmission of multiple paths of data is achieved only by using base station side cooperation and through combined design of precode emission and filtering wave receiving. At an emission end, two paths of interference signals carrying identical data information are aligned to opposite directions of the same sub-space through an IN, and interference signals carrying different data information are aligned to the same sub-space through an IA. A receiving end adopts orthogonal projection filtering waves to finish elimination of residual interference and recovery of the expectation data. In addition, the cooperative multi-point transmission method based on interference alignment and interference neutralization uses interaction of partial data, does not need user side cooperation, can make full use of space reuse capacity provided by multiple antenna systems, and achieves improvement in the handling performance of the systems.

A method and apparatus are provided for demodulating a received signal containing modulated desired-signal digital data and relayed-interference that results from a nonlinear-distorted interference signal. Estimation of the nonlinear-distorted interference from a pre-distortion interference signal and subsequent cancellation within the received signal of the distorted interference produces a residual-interference signal that is subsequently demodulated to produce estimates of the desired-signal data. The estimation is adapted for changing nonlinear distortion effects.

The invention discloses a method for detecting the iteration of a multiple input multiple output (MIMO) system, a system thereof and a device thereof. The method comprises the following steps of: when initializing an iteration process, adopting a soft in soft out parallel soft interference cancellation MMSESIC MIMO detecting method with a signal which is received by a receiver and a channel fading matrix which is estimated by the channel; when continuing the iteration process, taking the sum of residual interference and noise which are deleted by the parallel soft interference as an equivalent noise with the signal which is received by the receiver, bit priori information which is outputted by a channel encoder in the former iteration and a channel fading matrix which is estimated by the channel, wherein, the each component of the equivalent noise is similar to be mutually independent gaussian random variables, and executing a soft in soft out MMSESIC MIMO detecting computation under the model; and hard deciding code bit posterior information which is outputted by the soft in soft out channel encoder, executing a CRC check, outputting the hard decision result of the information source code bit posterior information, and taking the result as the final result of interative detection.

The invention discloses a seal authenticity identification method capable of eliminating receipt interference, which comprises the following specific steps of: preprocessing a seal image; repairing a preprocessing result image; registering the seal image and a prestored standard seal image; performing expansion; filtering the image from which the receipt interference is eliminated; corroding the registered standard seal image at one time; eliminating the residual interference further; performing coarse discrimination on the authenticity of the seal image; and performing fine discrimination on the authenticity of the seal image. The authenticity identification method is suitable for bill seals under the actual stamped condition; the link of preprocessing the seal image mainly comprises that the interference such as receipt tables, characters and the like of bills which are superposed on the seal is eliminated, and the preprocessing link is completed by adopting steps of color extracting, the repair of signature superposition defect of the seal, the removal of local interference through filtering and the like; and in the identification of the authenticity of the seal image, an authenticity identification result is obtained according to the distribution character of a residual error ratio in a mode of defining left deviation and right deviation.

This invention discloses a dynamic interference guiding method, and mainly solves the problem that the data rate of a user is reduced due to overlarge power expense in the interference management method. The method comprises the following steps: channel state and data information among transmitters are shared; a target communication pair and an interference communication pair design a respective precoding vector and a filtering vector; a target communication transmitter calculates the precoding vector of the interference guiding signal, so that the direction of projection component of the interference guiding signal is opposite to the direction of projection component of the interference signal in the direction of an expected signal; and then, the optimal dynamic interference guiding coefficient is calculated; the interference guiding power expense and the residual interference are compromised; hereby, the dynamic interference guiding signal is constructed; the dynamic interference guiding signal and the expected signal are sent to the target communication receiver to realize interference dynamic guiding; and at last, the receiver restores expected data. Through reasonably distributing the transmitting power of the transmitter corresponding to the interfered receiver, the spectrum efficiency of the interfered receiver is maximized, and the method is used for transmitting data when the receiver is interfered.

The invention relates to a serial interference cancellation and detection method and system for a multi-antenna bit interleaved coding system. The system disclosed by the invention comprises an MMSE (Minimum Mean Square Error) equalization filter module, a post-detection signal-to-noise ratio computing module, a sequencing module, a data channel section module, a soft demodulation module, a data revaluation module, an interference cancellation module, a residual interference estimation module, a similar MMSE equalization filter module, a similar post-detection signal-to-noise ratio computing module and a judgment module. According to the method and the system, the technical problem that the residual interference of 'eliminated' interference is considered to be zero existing in the conventional serial interference cancellation method is solved. In the invention, a correct flow device is provided for an MMSE serial interference cancellation method, a residual interference estimation method is further provided, and a correct form for estimating the MMSE of data in residual layers and a corresponding computation form of a post-detection signal-to-noise ratio used in the presence of 'residual interference' are provided.

The invention discloses a user selection method in a multi-community multi-user interference channel system in the technical field of communication. The user selection method in multi-community multi-user interference channel system includes: firstly, obtaining an interference channel matrix from other communities to the users in the community, and combing the interference channel matrix into an interference channel matrix of the users of the community; resolving quick response (QR) sorting the interference channel matrix of the users of the community, and obtaining a corresponding upper triangular matrix and postprocessing matrix; using the upper triangular matrix to obtain a user channel mass matrix; obtaining optimal users through the user channel mass matrix; finally, obtaining a postprocessing matrix through the interference channel matrix corresponding to the optimal users. The user selection method in the multi-community multi-user interference channel system is capable of ensuring that the users can select the system, lowering calculating complexity of channel quality information of each user, increasing handling capacity of the system, obviously improving the residual interference after user selection, and improving feasibility of the method in practical application.

The embodiment of the invention provides an MMSE-IICPD (minimum mean-square error-iterative interference cancellation parallel detection) algorithm applicable to efficient calculation of symbol detection on a parallel transmission system, and relates to the technical field of communication. Under the condition that the detection performance is unchanged, the complexity of the algorithm is obviously reduced. The algorithm comprises the steps: performing interference cancellation FORMULA on the current detected symbol xi in N symbols x=[x1, ..., xN]<T> which are transmitted in parallel, and performing MMSE wave filtering on yi to obtain a filtering result: FORMULA, wherein f(i, new) is the ith row of an MMSE wave filtering matrix Fnew, and Fnew=DHH(HDHH+ N0IM)<-1>, f(i, new)=FORMULA, D=diag(d), d=[d1, ..., dN]<T> is a residual interference variance of x=[x1, ..., xN]<T>; calculating a measurement value omega new(ak) of the current detected symbol xi at all modulation constellation points ak according to the wave filtering result, and calculating soft judgment and the residual interference variance of xi for next iterative use according to the measurement value of xi at all the constellation points.

A system is provided with circuits and methods for dynamically reducing interference to maintain linear system operation and mitigate interference degradation to desired signal components. The system can include a binning subcircuit system configured to divide the digitized input signal into a plurality of spectral bins each having a power level. A power analysis subcircuit can be coupled to the binning subcircuit and configured to compare a collective power level of spectral bins to a threshold level that would produce nonlinear system operation. Based upon the collective power level exceeding the threshold level, outputting a gain control signal to a variable gain amplifier so that the system remains linear. This dynamic gain control can be applied to systems that receive and/or transmit signals. Residual interference components that degrade signal components can be dynamically removed by excision and the distortion introduced by the excision process can be reduced with equalization circuitry.

The embodiments relate to a method and a base station (110) for interference management in a cellular network (100) employing Space-Division uplink (UL) downlink (DL) Duplexing (SDD). The base station (110) assigns a plurality of Remote Radio Units (RRU) as Tx RRUs operable to dedicatedly transmit downlink signals to a plurality of UEs and Rx RRUs operable to dedicatedly receive uplink signals from the plurality of UEs at the same frequency band and same time as the transmission of the Tx RRUs. The base station then suppresses the interference caused by simultaneous transmission on the same frequency band by using a Tx spatial beamforming weighting matrix and a Rx spatial beamforming weighting matrix. In addition, the base station may perform cross-talk cancellation on the residual interference contained in the received signals by using the knowledge of the downlink traffic data.