1371 results about "Interference elimination" patented technology

A wireless communication device includes, in part, at least one antenna for receiving or transmitting a signal, and a cancelation circuit adapted to cancel or reduce the self-interference signal. The cancelation circuit includes, in part, a control block, N delay and attenuation paths, a combiner, and a subtractor. Each path includes a delay element and a variable attenuator whose attenuation level varies in response to a control signal generated by the control block. Each path receives a sample of the transmit signal and generates a delayed and attenuated (weighted) version of the sample signal. The combiner combines the N delayed and weighted versions of the sample signal to construct a signal representative of the self-interference signal. The subtractor subtracts the constructed signal from the received signal thereby the cancel or reduce the self-interference signal therefrom.

An apparatus and method for interference cancellation in a multi-antenna system are provided. A transmission apparatus includes a channel identifier, a scheduler, an interference canceller, and a transmitter. The channel identifier identifies channel information of each of a plurality of receiving ends located in a service area and neighbor cell interference information on each receiving end. The scheduler selects at least one receiving end. The interference canceller precodes transmitted signals in order to cancel interference between receiving ends located in the same cell and neighbor cell interference. The transmitter transmits the precoded transmitted signals to the selected at least one receiving end.

An apparatus and method for interference cancellation and synchronization maintenance over interference channel estimation in a communication system are provided. An interference channel estimator fixes synchronization and estimates an interference signal. An interference signal controller eliminates the estimated interference signal from a received RF signal. A synchronization unit unfixes fixed synchronization and tracks synchronization when the interference signal cancellation is stable. A data buffer stores data from which the interference signal is canceled.

In a method of canceling interference, a base station selects a known highest data rate user transmission from a received first signal containing a group of user transmissions. The known highest rate user transmission may be configured as one or more frames, each frame including a control preamble and a plurality of encoded sub-frames. The control preamble and encoded sub-frames may be decoded, and the decoded sub-frames may be used for removing interference caused by the known highest rate user transmission to all remaining transmissions of the group.

Interference cancellation is performed in a CDMA receiver by projecting a received signal onto a subspace that is orthogonal to a signal selected for removal. An interference matrix or a combined interference vector is used to construct an interference-canceling projection operator. Confidence weights may be provided to components of the interference matrix or the interference vector based on estimation errors or relative strengths of interfering signals. Complexity reduction of the orthogonal projection operator may be achieved by providing for simplifying approximations that remove terms and operations. A linear transformation operator may be applied to the rows and / or columns of the interference matrix or the interference vector prior to construction of the orthogonal projection. Interference cancellation techniques may be configured for processing signals in a transmit-diversity system or a receive-diversity system using time and / or frequency-domain implementations and space and / or wave-number implementations of the transceiver.

An Apparatus and a method for interference cancellation in a wireless communication system are provided. When a resource of an Interference Cancellation (IC) zone is allocated to a terminal traveling in a service coverage, resource allocation information relating to an IC zone of neighbor cells is gathered. Resource allocation information is generated relating to the resource allocated to the terminal comprising resource allocation information of the IC zone of the neighbor cells. The resource allocation information relating to the resource allocated to the terminal is transmitted to the terminal. Accordingly, when the interference is present, the interference cancellation is carried out to reduce the load on the terminal and enhance the reception performance.

An impluse response hmn(q) of each transmission path is estimated from N received signals rm (m=1, . . . , M) and a known signal (for a number of users equal to N, n=1, . . . , N). M×N matrix H (q) having hmn(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 [bn(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 wn(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 wn(k) to provide a log-likelihood ratio as a received signal from the user n from which interferences are eliminated.

Interference is cancelled from a baseband signal by synthesizing interference from estimated symbols in interfering subchannels. The estimated symbols are hard-coded, soft weighted, or zeroed, depending on the value of an estimated pre-processed signal-to-interference-and-noise ratio (SINR) in each subchannel in order to maximize a post-processed SINR. The estimated pre-processed SINR is obtained from averages of estimated symbol energies and estimated noise variances, or from related statistical procedures.

A multistage adaptive parallel interference canceller is disclosed. The multistage adaptive parallel interference canceller for a downlink receiver includes: a plurality of stages of interference cancellation units. Each of interference cancellation units includes: a matched filter for matching a signal from a rake receiver each channel signal and generating a matched signal; a soft decision unit of which a slope is monotonically increased, for performing soft decision of the matched signal and generating a soft-decided signal; a weight controller for controlling the slope of the soft decision unit; a respreader for respreading the soft-decided signal based on a walsh code and a scrambling code and generating a respread signal; an interference calculator for calculating interference signals due to another user signal and multipath signals; and an interference canceller for canceling the interference signals from an input signal received in the rake receiver.

The present invention provides a technique for cancellation of jammer signals in a radio frequency receiver. A radio frequency signal contains both a desirable signal and an undesirable jammer signal. The combined signal is processed with a filter (104) to extract only the undesirable jammer signal. The jammer signal is then added (104) back to the combined signal to effectively cancel the jammer signal. The system may be implemented using a feedforward approach or a feedback approach. The resultant clean signal is processed in a conventional manner.

The present invention relates to a method for cancelling adjacent cells interference signal in a wireless communication system. In one embodiment this is accomplished by receiving desired user signal and cancel the channel effect using the desired users reference and or pilot signals, by a serving base station, identifying interference power by estimating the interferer power, determining if the interference is more than threshold, monitoring the interference and identify the interferer signal, re-generating the interference signal source and perform the channel estimate for the interferer, and canceling the interference by applying the interference pattern and the channel estimate to the desired user who's interference is more than threshold.

The related method preventing subzone interference comprises: allocating corresponding frequency resource for subzone edge users applying interference coordination and interference elimination respectively, exactly, the frequency resource can be allocated in advance, or allocated when system business loading changes and satisfies a certain condition; then, adjusting the frequency resource for eliminating and coordinating interference. This invention makes full of two ways for avoiding interference, adds system flexibility, and supports wide business request.

A method and device for eliminating narrow-band interference in spread spectrum system, wherein the method comprises the steps of: extracting N sampling points of the data to perform frequency spectrum transform each time and obtaining N points of data; getting the energy sum of individual data after M times of transform, obtaining N energy values, in which M≧1; removing partial excessive large values from N energy values and averaging the rest, then calculating the threshold value for interference determination based on the average value; obtaining the identification information of the points that have energy values exceeding the threshold value from N energy values and performing interference suppression for the data of corresponding points after frequency spectrum transform and finally outputting the data after frequency spectrum inverse transform. The device comprises a frequency spectrum transform unit, an interference elimination unit, an interference elimination control unit and a frequency spectrum inverse transform unit. The present invention could exactly distinguish interference data from non-interference data and effectively suppress narrow-band interference.

The invention discloses a method and device for eliminating interference. The method comprises: judging whether frequency multiplication of interference source operating frequency causes interference on operating frequency of a system; and under the condition that the frequency multiplication of the interference source operating frequency causes interference on the operating frequency of the system, adjusting the interference source operating frequency. Through the method and the device, the problem that in correlation techniques, interference elimination methods cannot meet requirements is solved, and thus effect that interference elimination effect is better and cost is lower is achieved.

The invention relates to a system and a method for eliminating common station site interference. The system comprises a first coupler, a transmission unit, an adjustment unit, an offset unit and a detection control unit, wherein the first coupler is used for extracting a signal transmitted by an interference base station as an interference offset signal, and coupling the interference offset signal to the transmission unit; the transmission unit is used for transmitting the interference offset signal to the adjustment unit; the adjustment unit is used for carrying out time delay, amplitude andphase adjustment of the interference offset signal to ensure that the interference offset signal and an interference signal received by a receiver from the interference base station through a wireless path have identical amplitudes and 180-degree phase difference; the offset unit is used for adding the interference offset signal adjusted by the adjustment unit to the interference signal received by the receiver from the interference base station, thereby offsetting the interference signal from the interference base station; and the detection control unit is used for controlling the adjustmentunit to carry out time delay, amplitude and phase adjustment of the interference offset signal according to the interference signal received by the receiver from the interference base station.

Multi-user detection method with elimination of interference between users, each user transmitting modulated data in the form of symbols on a transmission channel, each transmission channel (k) comprising at least one propagation path (i) and each propagation path arriving at an array of reception antennae (l) according to a direction of arrival (θi,k), the method comprising at least one sequence of steps for each user (k), each sequence comprising:(a) a reception step (600k,700k,800k,800,900) decomposing each antenna signal into filtered signals (xl,i,k) issuing from the different paths (i) of the said user (k) and combining the said filtered signals by means of a first plurality of coefficients (bl,i,k, ci,k) in order to form an estimation (zk) of the signal transmitted by the user;(b) a step of estimating (670k,770k,870k,870,970) the contribution ((xl,k)l=1 . . . L) of the user to the signals received by the different antennae from the said estimation of the signal transmitted and a second plurality of coefficients (ui,k, wl,i,k ) obtained from the said first plurality of coefficients;(c) a step of eliminating interference (680k′,780k,880k,880,980) subtracting from the antenna signals the contribution estimated at step (b) in order to obtain cleaned antenna signals;the cleaned antenna signals supplied by at least one first sequence being used as antenna signals by at least one second sequence.

Systems and methods of satellite communications for moving terminals, including but not limited to on-the-move and mobile terminals (e.g., on-the-pause terminals), are implemented in certain embodiments using smaller antennas (e.g., aperture area with diameter less than 50 cm), open standard waveforms to secure availability from several suppliers, payment for service only when using the terminal, interference avoidance to adjacent satellites, and low cost. Low cost is achieved in part by operating at frequency bands that are currently operated by terrestrial microwave links so that existing low cost microwave components are utilized. The system also includes an interference elimination system that continuously monitors for interference to adjacent satellites from a user terminal's uplink signal. If interference is detected, the interference elimination system remedies the interference by performing one or more of the following: shutting down the interfering terminal(s), changing transmission parameters, changing the beam coverage on ground, changing the frequency of the affected traffic, or moving the satellite to a new orbital position. The interference elimination system may also transit the interference information to a control center.

For providing a module for use of a mobile communication terminal, being small in sizes and high in reliability, and enabling with plural numbers of bands, and also a mobile communication terminal with using the same therein, canceling is conducted on transmission signal and / or noises of reception band on reception side with using a feed forward technology, for maintaining a degree of suppression of the transmission signal and / or the noises of reception band on the reception side. In this case, for achieving the cancellation of wide band signals from the transmission signal to the reception band, a delay adjusting function is used, in addition to gain and phase adjusting functions. Also, for conducting stable canceling of jamming signals, controls are conducted on the gain, the phase and the delay of a loop with using a reception SN and / or a CQI signal, etc.Further, for achieving low power consumption, a feed forward loop can be made ON / OFF depending on a level of the transmission signal.

The present invention relates to an interference cancellation receiving method in an OFDMA mobile communication system, and an apparatus using the same. For this purpose, the present invention provides an interference cancellation receiving method for outputting a data symbol from which an interfering signal is canceled by receiving subcarriers including a data signal from a serving base station, the data signal including interfering signals from a neighboring base station and a remote base station, estimating a channel response of the serving base station and the neighboring base station by using at least one adjacent pilot subcarrier in the frequency axis or time axis, computing a weight value for canceling the interfering signals, and combining at least one data subcarrier having a repeated identical data symbol among received subcarriers with the weight value. According to the present invention, performance of receiving serving base station signals is improved, and a success rate of handoff is increased and handoff delay time is reduced by successful decoding of signals from a serving base station and a neighboring base station when handoff occurs.

The invention discloses a multi-access interference elimination method of an uplink multiuser MIMO system, which relates to an advanced long term evolution system (LTE-Advanced). At the reception end of a base station, a null space matrix is obtained by utilizing the channel state information of the paired users and then constructed into a transformation matrix which does not reduce the channel multiplexing degree; and the transformation matrix is utilized to process a received signal so as to eliminate the multi-access interference between the paired users. When the users are scheduled, the different users using the same codebook are restricted from occupying a same time frequency resource and the probability that the users with relatively larger channel relativity are paired with each other is decreased, so as to minimize the influence of the transformation matrix on the effective signal strength. Simulation shows that the invention can remarkably reduce the multi-access interference of the uplink multiuser MIMO system, improve the signal to noise ratio of the user and enhance the system throughput.

A method and apparatus for noise cancellation in communications systems. The method is applicable in situations where an interfering signal or noise must be cancelled within a specified bandwidth. A sample of the interfering signal is used to synthesize a cancellation signal which is of equal amplitude but opposite phase to the original interference signal. Introduction of the cancellation signal into the interference signal path results in substantially complete suppression of the interference signal through vector subtraction of the superposed signal fields. Adaptive cancellation is also provided in that the frequency and bandwidth of the cancellation signal can be controlled. The adaptive nature of the cancellation loop also tracks out imbalances between the interference and cancellation signals caused by temperature variation and component tolerances. The adaptive nature of the cancellation system also allows the system to lock onto and track an interfering signal.

The present invention is directed to signal cancellation in spread spectrum communication systems. In particular, the present invention provides method and apparatus for selectively canceling interfering signals, even where symbols to be canceled do not align with symbols associated with a desired signal path. Furthermore, the interference cancellation provided by embodiments of the present invention is capable of functioning to remove interference associated with channels utilizing a symbol length that is different than the symbol length of a desired signal path. In accordance with a further embodiment of the present invention, method and apparatus for efficiently calculating projections to enable signal cancellation are provided.

The invention relates to a universal road and lane detection system and method. The method comprises: S300, interference elimination and image artifact and irrelevant image part removing are carried out on an input image to obtain a relevant image; S302, lane edge feature or road edge feature is extracted from the relevant image; S304, according to the lane edge feature or road edge feature, fitting is carried out to obtain a synthesized path expression model; S306, the path expression model is tracked to carry out time sequence consistency integration or position consistency integration; and S308, the path expression model corresponds to a global coordinate system. On the basis of the module design, pretreatment is carried out on the image inputted by the camera, the interested relevant image is selected; lane detection or road detection is carried out by combining input information of the laser radar; model fitting is carried out to estimate a road path and the accuracy of path estimation is improved by using the time sequence integration module; and then the image corresponds to the global coordinate system in real time by using a coordinate system correspondence module to improving path estimation accuracy. Therefore, a problem that the existing road estimation model has imperfect functions can be solved.

The invention relates to a terminal access method, device and system in a wireless communication system. In the invention, a base station of the wireless communication system carries out a transceiving operation by using a primary channel and a secondary channel, and a periodicity of the base station is switched between the primary channel and the secondary channel. The method also includes the following steps: after the terminal to be accessed determines that the access operation is not completed through the primary channel of the base station, an interference state of the primary channel of the base station is detected. The detecting result of the interference state is transmitted to the base station by the secondary channel of the base station, and the interference state is eliminated by the base station according to the testing result of the interference state. After an operation of interference elimination, the base station notices the terminal to implement the access operation through the primary channel again. Therefore, the invention is able to improve a success rate of the terminal access in the base station system, and on the other hand, the invention is able to reduce dead zones of the communication system and thereby to improve communication performance of the wireless network.

In a co-channel deployment of narrowband and multi-carrier technologies (e.g., a femtocell and a macrocell), a method provides cancelling of interference which treats the co-channel signals as desired signals and enhances each of them iteratively. At each iteration, each signal is demodulated and regenerated based on symbol decisions already made and a predetermined channel impulse response. To estimate the other (interfering) co-channel signal, the regenerated signal is subtracted from the aggregate signal. Simulations have shown that a method of the present invention can provide fundamental improvement in the performances of both interfering systems in as few as two iterations. The fundamental performance gain that can be obtained outweigh the required computational burden.

Cancellation of interference in a communication system with application to S-CDMA. A relatively straight-forward implemented, and computationally efficient approach of selecting a predetermined number of unused codes is used to perform weighted linear combination selectively with each of the input spread signals in a multiple access communication system. If desired, the predetermined number of unused codes is always the same in each implementation. Alternatively, the predetermined number of unused codes are selected from within a reordered code matrix using knowledge that is shared between the two ends of a communication system, such as between the CMs and a CMTS. While the context of an S-CDMA communication system having CMs and a CMTS is used, the solution is generally applicable to any communication system that seeks to cancel narrowband interference. Several embodiments are also described that show the generic applicability of the solution across a wide variety of systems.

The invention discloses a non-orthogonal multi-user access and sending and combined receiving, demodulation and coding system and method, and belongs to the technical field of communication. The method is characterized in that at a sending end, multiple users have access to the system in a non-orthogonal mode, and channel coding, coded symbol mapping, interleaving and modulation are carried out on a signal; at a receiving end, the received signal is multiplied by the feature sequence of each user, multi-user detection, demodulation, de-interleaving and decoding are sequentially carried out on the received signal, then multi-user detection is carried out on an output result again, and the iteration process is achieved. Based on the message passing conception, output soft information of a decoder is directly sent to undergo multi-user detection so as to achieve decoding and multi-user detection combined iteration processing. By means of the method, based on linear computation complexity, good interference elimination performance can be achieved, influence, caused by environmental noise and interference, on signal information is effectively reduced, and good BER performance and a more reliable transmission effect are achieved; meanwhile, multi-user interference elimination and decoding can be combined to be carried out, and therefore a parallel structure can be easily realized.