65 results about "Virtual antenna array" patented technology

A cooperative spatial multiplexing scheme in which the transmitter (source), equipped with a single antenna, forms virtual antenna arrays from a collection of distributed antennas belonging to different wireless terminals, and transmit a high-rate data stream to those terminals (relays). Each relay detects only a subset (called sub-stream) of the data stream and all relays forward their sub-streams simultaneously over the same physical channel. Then the receiver (destination) nulls and cancels the interference from different relays in order of the magnitude of log-likelihood ratio and detects the signal transmitted from the source.

A surveillance apparatus for determining a position of an object in a field of view, comprising a radar sensor having at least on transmitting antenna configured to transmit electromagnetic radiation and a plurality of receiving antennas configured to receive electromagnetic radiation, wherein the receiving antennas form a virtual antenna array, and a processing unit connected to the radar sensor to receive signals from the receiving antennas corresponding to the received electromagnetic radiation, wherein the processing unit is configured to determine a correlation matrix on the basis of the received signals, and wherein the processing unit is configured to determine a direction of a position of the object in the field of view with respect to the radar sensor on the basis of the correlation matrix for a defined distance of the object from the radar sensor.

A localization method for use in a tag communication system includes associating a supertag having a plurality of tags with an item, reading backscatter signals from the tags of the plurality of tags to provide a plurality of backscatter signals, estimating a signal parameter of the backscatter signals of the plurality of backscatter signals to provide a plurality of derived signal parameters, and localizing the item in accordance with the plurality of derived signal parameters. The backscatter signals are read by a tag reader having a single antenna and the item is localized in accordance with an antenna array technique performed upon the plurality of derived signal parameters. The backscatter signals are read with an antenna array to provide a further plurality of derived signal parameters for each tag of the plurality of tags, and the item is localized in accordance with the further pluralities of derived signal parameters.

The invention discloses a high-precision wireless channel test bench based on a virtual antenna array and a method thereof. An antenna system adopts the virtual antenna array technology based on an electronic control wave beam scanning antenna, adjusts the wave beam direction of the antenna wave beam in a horizontal zone and a vertical zone by a voltage control signal, adjusts the physical position of the antenna by a rotation controller, measures the airspace in a scanning mode, collects actual-measurement channel response and obtains the fine grain characteristic of the channel in the time domain and the airspace so as to provide effective parameter for practical channel analysis and modeling. The invention improves the switching speed of the antenna array and increases the accuracy of channel test.

A surveillance apparatus includes an optical camera that captures images based on received light, the optical camera including a camera aperture and a radar sensor including one or more transmitting antennas configured to emit electromagnetic radiation and one or more receiving antennas configured to receive electromagnetic radiation. The one or more transmitting antennas and the one or more receiving antennas form a virtual antenna array. The one or more transmitting antennas and the one or more receiving antennas are arranged such with respect to the optical camera that the center area of the virtual antenna array and the center area of the camera aperture coincide.

The invention discloses a virtual array antenna based angle estimation method for improving accuracy. The virtual array antenna based angle estimation method is used for a large-scale uniform linear array based millimeter wave communication system, and the sparse characteristics of millimeter wave channels and a compressing reconstruction algorithm are utilized to estimate an antenna transmitting angle and an arrival angle of each channel of multiple channels by adding a plurality of virtual array elements on antenna arrays at the receiving end and the transmitting end. By means of the virtual array antenna based angle estimation method, the angle estimation accuracy can be improved, pilot frequency sequence expenditure can be reduced, and antenna array hardware change is not needed.

The invention discloses a virtual MIMO communication method based on terminal direct connection. According to the method, good channels can be acquired based on the short distance characteristic of terminal direct connection technologies, fading is small, and data forwarding expenditure of a base station is not avoided. D2D terminal cooperative communications are adopted, idle users around a communication terminal are used as auxiliary antennae of the communication terminal, and virtual MIMO is formed to transmit Alamouti space-time codes and acquire diversity gain; due to the limitation of power dissipation per unit volume, a plurality of antennae can not be integrated at an actual terminal easily; a virtual antenna array for the terminal can be formed through the users around the terminal based on the D2D technology, the good channels can be acquired because the terminal is close to the peripheral idle users, and accordingly signals can be transmitted like being transmitted from the same terminal; meanwhile, at a receiving end, the performance of a system can be further improved by forming a receiving array through peripheral idle users.

The invention relates to the technical field of communication, and discloses a wireless network cooperative method, a wireless network cooperative system and a network node. The wireless network cooperative method comprises the following steps that: a source node determines at least one cooperative node; and the source node transmits data to the at least one cooperative node when transmitting thedata to a target node, so that the at least one cooperative node forwards the data to the target node on a reserved channel. By using the technical scheme provided by the embodiment of the invention,a plurality of cooperative nodes can participate in cooperative communication to generate a virtual antenna array so as to reach MIMO gains.

The invention discloses a linear constraint virtual antenna beam forming method. The method comprises the following steps: to begin with, carrying out pre-estimation on rough orientations of M interferences reaching an array antenna; determining a transformation region theta, and carrying out interpolation transformation according to manifold relationship of an actual array and a virtual array to obtain a transformation matrix; obtaining a covariance matrix of the virtual array by utilizing the transformation matrix; carrying out forward-backward spatial smoothing treatment on the covariance matrix of the virtual array; constructing a correlation matrix of steering vectors in an interpolation transformation region, extracting feature vectors corresponding to larger characteristic values in the correlation matrix and carrying out linear zero-setting constraint on the extracted feature vectors; and calculating the optimal weight vector and forming a wave beam. The method can greatly deepen nulling depth of the wave beam formed by the virtual array, reduce side lobe level, improve output SINR(signal to interference plus noise ratio), effectively suppress interference of super array freedom degree and improve anti-interference performance of the virtual antenna array.

The invention discloses a relative motion trajectory tracking-based Wi-Fi gesture recognition method. The method comprises the following steps of: firstly, detailedly analyzing an error source included in a phase of channel state information (CSI) obtained by a system, and completing error elimination by utilizing estimated values of a slope and an intercept; secondly, putting forward a new data fusion-based iterative interference suppression algorithm by utilizing the error eliminated channel state information so as to complete interference elimination of reflected signals and direct signalsbetween a transmitter and a receiver; thirdly, capturing signals reflected by a motion gesture by the system on the basis of interference suppression, constructing a virtual antenna array by utilizingcontinuous time signals received in a time domain, estimating wave incoming directions of the signals by utilizing a two-dimensional space smooth MUSIC algorithm, and reconstructing a motion trajectory of the gesture; and finally, completing gesture recognition by utilizing a Gaussian kernel-based support vector machine classifier according to the reconstructed motion trajectory. Experiments andanalysis results prove that the iterative interference suppression algorithm is capable of effectively suppressing interference signals, and a virtual array technology is put forward, so that overheads of reception-end antennas can be greatly decreased on the basis of improving the resolution and then the reconstruction of gesture motion trajectories is completed; and meanwhile, the method is notonly capable of completing single-hand gesture recognition, but also capable of correctly completing double-hand gesture recognition, and can better satisfy the requirement for gesture recognition inman-machine interaction.

A joint sounding mechanism used in a multi-AP system to gain channel information for joint data transmission. Multiple sounding APs can transmit a joint sounding packet that includes training symbols for the antennas of all the sounding APs with regard to the transmission channel. The antennas of the multiple sounding APs may be treated as a virtual antenna array with global antenna indexes. The joint sounding packet may include a plurality of training fields, each field corresponding to a respective antenna in the virtual antenna array. Alternatively, the joint sounding packet has subcarrier-interleaved training fields, where each sounding AP transmits training symbols on an allocated set of non-pilot subcarriers. Channel status information (CSI) can be generated by the STAs in response to the joint sounding packet and supplied to the APs. Accordingly, the APs can perform antenna beamforming and transmit a data packet jointly on the transmission channel.

In the field of distributed wireless sensor network long-distance communication, the communication distance and the energy of a single node are limited, a multi-hop mode is used, bit error rate is high, and time delay is large. Accordingly, the invention discloses a cooperative communication mode of wireless sensor network beam forming transmission and a node selecting method. First, the smallest node number needed for forming a virtual antenna array is determined; then an ideal antenna direction picture of the array is determined, according to the ideal direction picture, the conditions such as array shapes and node space distance are determined, and nodes which accord with the conditions are selected to form the antenna array; and finally the nodes are managed, array nodes are coordinated, time sequence is unified, and data are sent in a combination mode in a beam forming manner. According to the method, the problem that time delay is too high, and energy loss is too large due to traditional wireless sensor network long-distance multi-hop communication can be effectively avoided, communication success probability is improved, and network lifetime is prolonged.

The invention provides a method for calculating a moving target angle of a time division multiplexed MIMO radar. According to specific time division multiplexing time sequences of a transmitting antenna array element and a receiving antenna array element, a virtual antenna array obtains all rounds of receiving signals according a first array element, a second array element, a third array element,a fourth array element, ..., and an MNth array element; and each round of receiving signal obtained by the virtual antenna array is processed as follows: step a, distance direction processing is carried out to obtain a distance direction signal; step b, first digital beam forming processing is carried out, a virtual beam array in which a target is located is extracted by a target detection methodand is synthesized with the distance direction signal, and the target speed is calculated; step c, phase compensation is carried out on the distance directions signal of the target; and step four, second digital beam forming processing is carried out and then a correct angle of the target is calculated. According to the invention, no redundant virtual array element needs to be designed and angle calculation of the low-signal-to-noise-ratio target is realized.

The invention provides a radar signal processing method which comprises the steps: arranging a millimeter wave radar virtual antenna array, wherein periodic deviation exists between the actual phase difference and the measurement phase difference when the azimuth angle is larger than the measurement azimuth angle of the virtual antenna; measuring the phase difference, and calculating a fuzzy azimuth angle according to a phase method angle measurement principle; substituting the fuzzy azimuth angle into a pitch compensation phase difference formula to obtain a pitch compensation phase difference, compensating the antenna array element by utilizing the pitch compensation phase difference, and then obtaining a pitch angle according to the phase method angle measurement principle; substituting the pitch angle into a pitch compensation phase difference formula to obtain a direction-dimensional pitch compensation phase difference, performing phase compensation on the antenna array element by utilizing the direction-dimensional pitch compensation phase difference, and then obtaining an unambiguous azimuth angle according to the phase method angle measurement principle; and comparing the fuzzy azimuth angle with the non-fuzzy azimuth angle, and obtaining a true value of the pitch angle when the two angles are equal. The large FOV and the high angle resolution can be achieved without additionally increasing the number of antennas, and the contradiction between the angle resolution and the azimuth angle range is effectively reconciled.

The invention discloses a virtual antenna array-based Doppler spread compensator and a virtual antenna array-based Doppler spread compensation method. The virtual antenna array-based Doppler spread compensator comprises N k-dimensional antenna arrays, a speed-providing unit, a timing unit, N interpolation units, a receiving unit, a transmission unit and N extrapolation units; the N k-dimensional antenna arrays are used for receiving and transmitting first signals; the speed-providing unit is used for constantly providing the flight speed v of a plane; the timing unit is used for constantly providing the flight time t of the plane; the N interpolation units are used for obtaining N second signals according to the positions of N virtual receiving antennas in the N k-dimensional antenna arrays and the least mean square error algorithm; the receiving unit is used for receiving the N second signals; the transmitting unit is used for providing signals to be transmitted; and the N extrapolation units are used for obtaining N third signals output to N virtual transmission antennas. The Doppler spread compensator can effectively compensate the Doppler shift and the frequency spread generated in air-to-ground aeronautical communication and obtain multi-antenna gain.

The invention discloses an unmanned aerial vehicle relay communication method based on virtual array antenna cooperative beam forming. The method comprises the following steps: 1, determining the number of unmanned aerial vehicle nodes forming an unmanned aerial vehicle antenna array; 2, determining an azimuth angle and an elevation angle according to positions of the unmanned aerial vehicle nodes and a position of a remote base station needing communication; 3, establishing a calculation model of a transmission rate from the unmanned aerial vehicle antenna array to a receiving base station, a calculation model of the maximum sidelobe level of the unmanned aerial vehicle antenna array and a calculation model of energy consumption of a unmanned aerial vehicle, and determining optimal positions of the unmanned aerial vehicle nodes, an optimal base station communicating with the unmanned aerial vehicle antenna array and an optimal excitation current weight by taking the maximum transmission rate from the unmanned aerial vehicle antenna array to the receiving base station, the minimum maximum sidelobe level of the unmanned aerial vehicle antenna array and the minimum energy consumption of the unmanned aerial vehicle as optimization targets; and 4, after the unmanned aerial vehicle nodes move to the optimal positions, forming a virtual antenna array and transmitting data to the optimal base station by utilizing cooperative beam forming.

The invention discloses an inverse time inversion-based through-the-wall radar reference surface correction method. An oblique angle between an antenna array and a horizontal plane and a vertical distance between the array center of the antenna array and a wall body are estimated according to echo time delay; the coordinates of antenna array elements and a horizontal reference surface are determined; the oblique antenna array is expanded to the horizontal reference surface according to the inverse problem principle of electromagnetic wave propagation; and echo signals received by a virtual antenna array located at a horizontal measurement line are adopted to replace echo signals received by the antenna array located at an oblique measurement line, so that real scene imaging can be realized. According to the inverse time inversion-based through-the-wall radar reference surface correction method, a wave equation is adopted, so that the condition of electromagnetic wave propagation in space can be described more authentically; and the oblique antenna array is extended to the horizontal reference surface, and therefore, influence of target dislocation and distortion caused by the oblique antenna array can be effectively eliminated. Compared with the prior art, the inverse time inversion-based through-the-wall radar reference surface correction method has the advantages of higher imaging precision, easiness in implementation and great significance in practical application.

The invention discloses a two-dimensional MIMO antenna array, which forms an equivalent virtual receiving antenna array by reasonably arranging transmitting antennas and receiving antennas. By means of multi-input multi-output antenna array characteristics, multiple transmitting antennas and multiple receiving antennas are equated with an equivalent virtual antenna array having a single transmitting antenna and multiple receiving antennas through reasonable layout. Therefore, the number of actual antennas is decreased, and the problem is fundamentally solved that the antenna array has a largesize, a large number of antennas, and a complicated receiving system.

Disclosed is a method and apparatus for estimating a signal source, the method including receiving, in at least one receiving node, a signal emitted from a signal source, extracting a steering matrix corresponding to a virtual antenna array by vectorizing the signal received in the at least one receiving node, and estimating a location of the signal source based on the steering matrix.