39results about How to "Against interference" patented technology

The application discloses a method and a device for sending data. The method comprises the following steps: dividing at least one OFDM (Orthogonal Frequency Division Multiplexing) symbol pair in the temporal frequency resource of the current subframe, and forming a resource element (RE) pair by two adjacent resource elements on the same subcarrier in the same OFDM symbol pair; setting at least one resource element pair as a reference signal resource element pair, and setting at least one resource element pair as a data resource element pair; when sending signals corresponding to OFDM symbols are generated, adding a first circulating guard interval before first resource elements in the reference signal resource element pair and the data resource element pair, and adding a second circulating guard interval behind second resource elements in the reference signal resource element pair and the data resource element pair; forming a sending frame by the sending signals corresponding to the generated OFDM symbols and sending the sending frame out. The transmission quality of downlink data and a reference signal can be improved by the technical scheme which is disclosed by the application.

A synchronous method of orthogonal frequency division multiplexing symbol timing for multi-path fading channel environment, which is specially used for the OFDM system under the multi-path fading channel environment. Concretely, it includes following steps: 1) judging time range of the window starting point of effectively sampling for non-symbol interference in receipt signal; 2) processing preliminary sampled signal, using it to recover the OFDM signal; 3) obtaining the symbol timing estimate by coherent detection. The invention can effectively confront the inter-symbol interference produced by the multi-path fading, and can obtain comparatively accurate timing estimate under low SNR condition, which solves the problem of lowered synchronization property caused by the disrupted dependence of circulation prefix for complex channel environmental low system's SNR in prior art.

The invention discloses an orthogonal time-frequency space OTFS modulation equalization method with low computational complexity, which is a method for equalizing interference between two-dimensionalcodes of an orthogonal time-frequency air conditioner under a time-frequency double-selection channel based on iterative parallel interference elimination of a linear minimum mean square error. The method can effectively utilize the covariance matrix of the reconstructed symbol to alleviate the influence of the interference between the residual two-dimensional codes on the OTFS system performance,so that the time-frequency two-dimensional gain can be better utilized, and the system reliability can be improved; time-frequency two-dimensional decomposition and octyl Fourier transform are adopted to carry out first-order Newman series approximation on the inverse matrix in LMMSE-PIC, so that the calculation complexity of the equalization method is reduced, and the equalization method only has a directrix relation with the total number of transmission symbols and is irrelevant to the channel sparsity, so that the system effectiveness is improved. The orthogonal time-frequency air conditioning system has the advantages that the time-frequency two-dimensional diversity gain of the orthogonal time-frequency air conditioning system can be remarkably improved under the time-frequency double-selection channel, the receiver performance of the non-ideal channel decoder during feedback is improved, and the popularization and application prospect is good.

The invention relates to a time division duplex transmission method for a broadband wireless communication system, belonging to the technical field of digital information transmission. The method comprises the following steps: using a time / frequency-domain unified orthogonal frequency division multiple access (TFU-OFDMA) technology to carry out downlink multiple access so as to obtain downlink signals at a transmitting end of a base station; using a time / frequency-domain unified single carrier multiple access (TFU-SCMA) technology to carry out uplink multiple access so as to obtain uplink signals at a transmitting end of user equipment; and using a time division duplex frame structure to carry out duplex transmission on the downlink signals and the uplink signals. The TFU-OFDMA technology provided by the invention solves the multiple access problems in the TFU-OFDM (Time / Frequency-domain Unified Orthogonal Frequency Division Multiplexing) modulation process, can flexibly allocate wireless resources and can effectively overcome deep fade, narrow-band interference and the like. The TFU-SCMA technology provided by the invention solves the multiple access problems in the improved SC-FDE (Single Carrier Frequency Domain Equalization) modulation process, reserves the advantages of low complexity of the transmitting end in the SC-FDE technology, low peak-to-average power ratio and the like, and enables the receiving end to be subject to synchronization and channel estimation better.

The invention relates to a multiple access signal transmission method for a broadband wireless communication system, belonging to the technical field of digital information transmission. The method comprises the following steps of: respectively carrying out channel coding and digital modulation on transmission block data of a user on each path to obtain digitally modulated information; mapping the information and the pilot frequency of the user to corresponding data subcarrier and pilot frequency subcarrier, dividing all the data subcarriers into a plurality of subchannels to ensure that the information of each user corresponds to one or more than one subchannel, and setting protection subcarriers and DC subcarriers to be 0; carrying out inverse discrete Fourier transform on all the subcarriers to obtain time domain signals; and combining a generated protection interval sequence and the time domain signals, converting into a serial data stream, and sending the serial data stream. The invention has the advantages of high synchronization speed, accurate channel estimation and the like; more users can be supported by using smaller access time delay, wireless resources can be distributed freely, depth fading and narrow-band interference can be effectively resisted, and multiple-user diversity gain can be realized conveniently.

The invention provides a power line carrier communication method based on frequency domain processing. The power line carrier communication method based on frequency domain processing comprises the steps of: establishing initial sending and receiving time synchronization based on specific zero-crossing characteristics and three-phase 120-degree phase difference characteristics of a power line; representing bit information as a continuous phase carrier frequency-modulated sinusoidal or cosine signal based on low-frequency square wave modulation; performing physical framing according to the bitinformation; mapping the bit information onto a low-frequency square wave signal composed of high and low levels at first, then, performing relatively high carrier modulation on the high level and thelow level separately, so that a final carrier modulation signal is formed, and sending at the zero-crossing time of the power line; and, synchronously starting a digital phase-locked loop to performfrequency demodulation according to the zero-crossing time by a receiving end, and simultaneously, performing final data decision output through fast Fourier transform by selecting a proper window. The method provided by the invention is low in cost and simple to implement; furthermore, all kinds of multi-path interferences and all kinds of noise and pulse interferences in a severe power line environment can be effectively resisted; and thus, reliable transmission of data information is realized.

The invention relates to a multi-dimension hybrid spread spectrum system and method based on a high speed bus and a graphic processing unit (GPU), belonging to the technical field of communication. The multi-dimension hybrid spread spectrum system comprises a transmitting unit, a GPU, a receiving unit and a data main control unit, wherein the transmitting unit comprises a transmitting antenna, a transmission radio-frequency module and a low and medium frequency / baseband transmitting module; the receiving unit comprises a receiving antenna, a reception radio-frequency module and a low and medium frequency / baseband receiving module; and the data main control unit comprises a high speed bus and a main control / buffer and display module. The invention adopts the technologies of multi-input and multi-output, space-time coding, parallel processing and high-speed transmission reception diversity, and combines a direct spread / frequency hopping hybrid technology, so that the overall system integrates the advantages of three dimensions of space, time and frequency, and the confidentiality and anti-jamming ability of the realized hybrid spread spectrum system are further greatly expanded; and very quick data transmission and quick code synchronization and code acquisition performance of the multi-dimension hybrid system are realized by the advantages of the high speed bus and GPU architecture.

The invention discloses an MIMO (Multiple-Input Multiple-Output) radar preference optimization netting method in a multi-surveillance area. Firstly, a surveillance area and a netting area are determined, an objective function is determined, and a reference point is set according to preference information; then, with the reference point as the guide, a particle swarm optimization algorithm based on preference is used for reasonably optimizing an antenna netting position; and finally, from outputted netting schemes, a netting method closest to the reference point is selected for reasonable radar netting. The surveillance performance of a preference surveillance area can be enhanced, and more radar optimization netting methods can be acquired.

The invention discloses a long-distance large-data-volume wireless communication method for unmanned aerial vehicles, which can not only realize digital transmission of wireless video data, but also counteract interference problems in wireless channels so as to improve the transmission reliability of the wireless transmission system. This method forms video data by superimposing the video images taken by the UAV and the performance parameters during the flight of the UAV; then compresses and encodes the video data, and finally transmits the encoded video data to the client, and the prediction-based HARQ algorithm is used for error control in wireless transmission, which can not only realize the digital transmission of wireless video data, but also use the prediction-based HARQ algorithm to control the error of the wireless transmission channel Control, can counteract the interference problem in the wireless channel so as to improve the transmission reliability of the wireless transmission system. It is suitable for popularization and application in the field of wireless transmission technology.

The invention discloses a channel estimation method for single carrier frequency domain equalization under a low energy dispersion multipath channel. A problem of channel estimation performance loss of an existing single carrier equalization system under a low energy dispersion multipath environment can be improved effectively by using the channel estimation method disclosed by the invention. Segmentation is carried out through setting a value of an approximate signal to noise ratio, different numbers of useful signal paths and different threshold values are selected in different signal to noise ratio intervals, and then time domain noise reduction processing of channel estimation is carried out. The channel estimation method disclosed by the invention is not only applicable to extracting the useful signal paths accurately in a high signal to noise ratio environment. In addition, when most of the useful signal paths are possibly submerged in noises and cannot be distinguished in a low energy multipath channel environment, the low energy multipath channel environment is divided into a high signal to noise ratio interval, a middle signal to noise ratio interval and a low signal to noise ratio interval by adopting the method, the useful signal paths can also be extracted accurately, and the performance of channel estimation is improved.

The invention provides a communication system and signal sending method and apparatus as well as signal receiving method and apparatus thereof. The signal sending method comprises: based on channel information, carrying out channel coding and constellation mapping on each sub-data stream to be sent, carrying out multiple input multiple output sending process on the sub-data stream which has been subjected to the channel coding and constellation mapping, and carrying out OFDM modulation on the sub-data stream which has been subjected to the multiple input multiple output sending process, and outputting OFDM symbol data stream obtained after the OFDM modulation to a transmitting antenna for transmitting. The OFDM modulation comprises the sub-data stream which has been subjected to the multiple input multiple output sending process is inserted with pilot symbols of corresponding antenna ports and is mapped to corresponding physical subcarriers; and subcarriers in element units corresponding to the sub-data streams are expanded to whole or partial system bandwidth to form mapping with the physical subcarriers based on the preset mapping relation. The technical scheme in the invention is capable of effectively resisting the influence of frequency selective fading.

The invention relates to a system and a method for eliminating intersymbol interference of an ultrawideband signal of a multi-path noise-free channel. By setting an appropriate threshold value, a receiver searches an ultra-wideband signal pulse, and the detection is succesful until a signal level exceeds the threshold value; then, a signal window is used for extracting a received signal, and a detected composite signal pulse (formed by mixing a signal pulse and more than one multipath interference signal) is placed in the middle of the signal window; the received signal is processed through anintersymbol interference (ISI) eliminator before demodulation, so that the intersymbol interference is eliminated. According to the method, channel information or channel estimation does not need tobe acquired in advance, and analog-digital conversion is not needed; the expected signal pulse and the interference pulse can be distinguished and accurately positioned through the method; and a traditional receiving pulse is not used during signal demodulation, and a signal peak generated after wavelet transformation and high-pass filtering is used.

The invention provides a soft spreading code optical selection method of a mixed spread spectrum multiple-access network; the method comprises the following steps: setting limit conditions according to structure characteristics of a cyclic shift keying (CCSK) code, and forming a code database satisfying proportionality and autocorrelation requirements; employing an origin traversal-initial random-end segment directed segmented search method to screen a set of soft spreading codes satisfying cross correlation requirements from the autocorrelation code database; finally combining with a frequency hopping pattern so as to reasonably distribute the soft spreading codes to each network for usage. The method can effectively reduce the internetwork interferences, thus improving the system networking ability.

The invention belongs to the technical field of radar signal processing, and discloses a target detection waveform optimization and processing method for an agile coherent radar, which comprises the following steps of 1, optimizing a baseband signal waveform in a pulse of the agile coherent radar by using a nonlinear frequency modulation signal waveform, 2, establishing an echo model based on the agile coherent radar after waveform optimization, and obtaining an echo matrix, 3, performing pulse compression processing on the agile coherent radar after waveform optimization to obtain a pulse compression matrix, and 4, conducting coherent processing on the agile coherent radar after waveform optimization, and realizing improvement of target detection performance of the agile coherent radar. According to the method, the target detection performance of the agile coherent radar is improved in a strong clutter and strong interference environment, active deception jamming and aiming suppressing jamming of the radar can be effectively resisted, the detection distance farther than that of a non-coherent frequency agile radar can be achieved, and higher real-time performance is achieved by adopting a coherent accumulation algorithm.

The invention discloses a power control method and a power control device. The method comprises the following steps: determining a cross-link interference power compensation subitem, wherein the cross-link interference power compensation subitem is used for adjusting uplink sending power of UE; based on the cross-link interference power compensation subitem, determining an uplink power control algorithm, wherein the cross-link interference power compensation subitem is introduced into the uplink power control algorithm; and based on the uplink power control algorithm, performing uplink power control for the UE.

The invention relates to a high-accuracy pulse power detection module which comprises a radio-frequency circuit for receiving a radio-frequency input sampling signal and a radio-frequency output sampling signal. An output end of the radio-frequency circuit is connected with an input end of a detection circuit for receiving sampling voltage V1 and sampling voltage V2, and an output end of the detection circuit is connected with a fault indication circuit. The high-accuracy pulse power detection module can simultaneously detect an over-temperature connecting point, voltage V1 sampling, voltage V2 sampling, radio-frequency input sampling and radio-frequency output sampling, can monitor input and output power variation of a forestage component in real time to accurately judge whether input power and output power are faulted or not, voltage stability can be monitored in rear time to accurately judge whether an under-voltage condition exists as voltage reduces or not, no power output is caused, fault reasons can be effectively and rapidly found, and the component is conveniently maintained.

The invention discloses an orthogonal time-frequency space OTFS modulation equalization method with low computational complexity, which is a method for equalizing interference between two-dimensionalcodes of an orthogonal time-frequency air conditioner under a time-frequency double-selection channel based on iterative parallel interference elimination of a linear minimum mean square error. The method can effectively utilize the covariance matrix of the reconstructed symbol to alleviate the influence of the interference between the residual two-dimensional codes on the OTFS system performance,so that the time-frequency two-dimensional gain can be better utilized, and the system reliability can be improved; time-frequency two-dimensional decomposition and octyl Fourier transform are adopted to carry out first-order Newman series approximation on the inverse matrix in LMMSE-PIC, so that the calculation complexity of the equalization method is reduced, and the equalization method only has a directrix relation with the total number of transmission symbols and is irrelevant to the channel sparsity, so that the system effectiveness is improved. The orthogonal time-frequency air conditioning system has the advantages that the time-frequency two-dimensional diversity gain of the orthogonal time-frequency air conditioning system can be remarkably improved under the time-frequency double-selection channel, the receiver performance of the non-ideal channel decoder during feedback is improved, and the popularization and application prospect is good.

A multi-carrier MISO (Multiple Input, Single Output) system based on a three-dimension mutual-complementing code relates to an MISO system, and aims to solve the problem that a conventional MISO system is poor in multi-path interference resistance and multi-user interference resistance. Each user k adopts a three-dimensional mutual-complementing code as a signature code, each three-dimensional mutual-complementing code consists of NT two-dimensional mutual-complementing codes, and for each user k, the working procedures of the system comprises the steps as follows: step I, at a transmitting end, data to be sent is modulated to NT paths of modulation signals by utilizing a transmitter of the MISO system, and then the NT paths of modulation signals are transmitted to wireless signal channels via NT antennae; and steps II, at a receiving end, the transmitters of the MISO system is utilized to receive the NT paths of modulation signals transmitted to the wireless signal channels in the step I with one antenna. The system is applicable to the field of wireless communication.

The invention relates to a multi-dimension hybrid spread spectrum system and method based on a high speed bus and a graphic processing unit (GPU), belonging to the technical field of communication. The multi-dimension hybrid spread spectrum system comprises a transmitting unit, a GPU, a receiving unit and a data main control unit, wherein the transmitting unit comprises a transmitting antenna, a transmission radio-frequency module and a low and medium frequency / baseband transmitting module; the receiving unit comprises a receiving antenna, a reception radio-frequency module and a low and medium frequency / baseband receiving module; and the data main control unit comprises a high speed bus and a main control / buffer and display module. The invention adopts the technologies of multi-input and multi-output, space-time coding, parallel processing and high-speed transmission reception diversity, and combines a direct spread / frequency hopping hybrid technology, so that the overall system integrates the advantages of three dimensions of space, time and frequency, and the confidentiality and anti-jamming ability of the realized hybrid spread spectrum system are further greatly expanded; and very quick data transmission and quick code synchronization and code acquisition performance of the multi-dimension hybrid system are realized by the advantages of the high speed bus and GPU architecture.

The invention relates to a resource allocation method under high-speed rail train-mounted base station communication architecture. The resource allocation method aims at the train-mounted base station communication architecture, and is characterized by maximizing capacity of a communication system through resource allocation under an OFDMA (orthogonal frequency division multiple access) modulation mode. The resource allocation method under the high-speed rail train-mounted base station communication architecture mainly includes: establishing a capacity function under the high-speed rail train-mounted base station communication architecture; allocating subcarriers to a plurality of users; achieving subcarrier pairing for a base station end and a train-mounted mobile base station end; respectively allocating subcarrier power to the base station end and the train-mounted base station end. The resource allocation method under the high-speed rail train-mounted base station communication architecture is of great significance in system performance optimization under high-speed rail scene communication architecture.

The invention provides a soft spreading code optical selection method of a mixed spread spectrum multiple-access network; the method comprises the following steps: setting limit conditions according to structure characteristics of a cyclic shift keying (CCSK) code, and forming a code database satisfying proportionality and autocorrelation requirements; employing an origin traversal-initial random-end segment directed segmented search method to screen a set of soft spreading codes satisfying cross correlation requirements from the autocorrelation code database; finally combining with a frequency hopping pattern so as to reasonably distribute the soft spreading codes to each network for usage. The method can effectively reduce the internetwork interferences, thus improving the system networking ability.

The application discloses a data sending method and device. Among them, the method includes: dividing at least one Orthogonal Frequency Division Multiple Access (OFDM) symbol pair in the time-frequency resource of the current subframe, and two adjacent resource element REs on the same subcarrier in the same OFDM symbol pair form a Resource element pair; set at least one resource element pair as a reference signal resource element pair, and set at least one resource element pair as a data resource element pair; when generating a transmission signal corresponding to an OFDM symbol, make the reference signal resource element pair and A first cyclic guard interval is added before the first resource element in the data resource element pair, and a second cyclic guard interval is added after the second resource element in the reference signal resource element pair and the data resource element pair; the generated The sending signals corresponding to the OFDM symbols are composed into a sending frame and sent out. The technical solution disclosed in this application can improve the transmission quality of downlink data and reference signals.

The invention relates to a time division duplex transmission method for a broadband wireless communication system, belonging to the technical field of digital information transmission. The method comprises the following steps: using a time / frequency-domain unified orthogonal frequency division multiple access (TFU-OFDMA) technology to carry out downlink multiple access so as to obtain downlink signals at a transmitting end of a base station; using a time / frequency-domain unified single carrier multiple access (TFU-SCMA) technology to carry out uplink multiple access so as to obtain uplink signals at a transmitting end of user equipment; and using a time division duplex frame structure to carry out duplex transmission on the downlink signals and the uplink signals. The TFU-OFDMA technology provided by the invention solves the multiple access problems in the TFU-OFDM (Time / Frequency-domain Unified Orthogonal Frequency Division Multiplexing) modulation process, can flexibly allocate wireless resources and can effectively overcome deep fade, narrow-band interference and the like. The TFU-SCMA technology provided by the invention solves the multiple access problems in the improved SC-FDE (Single Carrier Frequency Domain Equalization) modulation process, reserves the advantages of low complexity of the transmitting end in the SC-FDE technology, low peak-to-average power ratio and the like, and enables the receiving end to be subject to synchronization and channel estimation better.

The present invention provides a modular and building block type digital array radar system. The system comprises a plurality of building block type digital active transceiver sub-modules and a data fusion server. The building block type digital active transceiver sub-modules are respectively mounted on a preset antenna array-plane framework and are respectively connected with the data fusion server. Each building block type digital active transceiver sub-module is composed of an antenna radiation module in card-inserting type connection with a comprehensive backboard, a digital T / R module, a digital beam forming unit, an optical power divider and an array-plane monitoring network module, wherein the antenna radiation module, the digital T / R module, the digital beam forming unit and the optical power splitter are sequentially in communication connection. The optical power splitter is connected with the data fusion server. The array-plane monitoring network module is respectively connected with the digital T / R module and the data fusion server. The modular and building block type digital array radar system has the advantage of multi-angle viewing angle and can effectively resist the main-lobe interference. A distributed arrangement receiving station is passive and can effectively reduce the radar intercepted probability and the radar attacked probability.

The invention discloses a method for estimating the direction of arrival of a polarization area array under main lobe interference based on spatial domain-polarization domain self-adaption. The method comprises the following steps of firstly, receiving data according to each array element of an area array to obtain a spatial domain-polarization domain joint adaptive weight, outputting data of a row of linear arrays, and then solving an azimuth angle of a target by adopting a maximum likelihood method algorithm; receiving data according to each row of array elements of an area array to obtain a spatial domain-polarization domain joint adaptive weight, outputting data of a column of linear array, and then solving a pitch angle of a target by adopting a maximum likelihood method algorithm. According to the method, multiple interferences in a main lobe can be resisted through spatial domain-polarization domain joint self-adaption, a problem that the target angle estimation precision is low due to the fact that spatial domain self-adaption under main lobe interference can cause main beam distortion is solved, and polarization self-adaption can only resist one interference in the main lobe although the main beam distortion cannot be caused.

The invention relates to a high-precision pulse power detection module, which includes a radio frequency circuit for receiving radio frequency input sampling signals and radio frequency output sampling signals, the output end of the radio frequency circuit and the input of the detection circuit for receiving sampling voltage V1 and sampling voltage V2 The output terminal of the detection circuit is connected with the fault indication circuit. The present invention can simultaneously detect the over-temperature contact, voltage V1 sampling, voltage V2 sampling, radio frequency input sampling, and radio frequency output sampling, and can monitor the input and output power changes of the front-stage components in real time, and then accurately judge whether the input power and output power are faulty, It can monitor the stability of the voltage in real time, and then accurately judge whether it is an undervoltage state caused by a voltage drop, resulting in no power output, which can effectively and quickly find the cause of the fault and facilitate maintenance.

The invention discloses a method of confronting active deception jamming by a multi-station radar. The method mainly comprises steps: after any node radar is selected to carry out matched filter and target detection on a receiving signal, K+M point targets are obtained, the first node radar serves as a reference radar, time alignment operation is carried out on the K+M point targets and the other N-1 node radars, and an echo amplitude corresponding relation between point targets detected by the N-1 node radars and point targets detected by the reference radar is obtained; echo amplitude of the pth point target on the nth node radar is selected, an amplitude ratio feature vector of the pth point target is obtained, false target determination is set to be a false alarm rate for a real target, a discrimination threshold theta for the N node radars is obtained, the amplitude ratio feature vector omegap of the pth point target is classified to be the pth class, and K+M different classes are obtained, clustering operation is carried out, and a final clustering result is acquired; and finally, a determination threshold value epsilon for false point targets is set, and the false point targets included in the final clustering result are acquired.

The invention discloses a channel estimation method for single carrier frequency domain equalization under a low energy dispersion multipath channel. A problem of channel estimation performance loss of an existing single carrier equalization system under a low energy dispersion multipath environment can be improved effectively by using the channel estimation method disclosed by the invention. Segmentation is carried out through setting a value of an approximate signal to noise ratio, different numbers of useful signal paths and different threshold values are selected in different signal to noise ratio intervals, and then time domain noise reduction processing of channel estimation is carried out. The channel estimation method disclosed by the invention is not only applicable to extracting the useful signal paths accurately in a high signal to noise ratio environment. In addition, when most of the useful signal paths are possibly submerged in noises and cannot be distinguished in a low energy multipath channel environment, the low energy multipath channel environment is divided into a high signal to noise ratio interval, a middle signal to noise ratio interval and a low signal to noise ratio interval by adopting the method, the useful signal paths can also be extracted accurately, and the performance of channel estimation is improved.

The present invention relates to a modulation and transmission method of biorthogonal interference, and is applied in the field of communication, so as to enhance the security of communication system. In the generalized Fourier series, the method adopts an algorithm of inverse transform to acquire the biorthogonal function family from a basis function; two groups of functions in the biorthogonal function family are respectively used at the receiving end and the transmitting end of the transmission system. The receiving end adopts one group of functions to complete the interference modulation of the signals; the receiving end adopts the other group of functions to complete the interference decomposition of the received signals, so as to acquire the information. The method can be used in the transmission system.