74 results about "Mimo channel matrix" patented technology

A system and method for opportunistically designing collaborative beamforming vectors is disclosed for a wireless multiple input, multiple output (MIMO) space division multiple access (SDMA) communication system by sequentially designing beamforming vectors for ranked channels in order to exploit the instantaneous channel conditions to improve per user average SNR performance. Each subscriber station independently transmits information to a base station that allows the base station to determine beamforming vectors for each subscriber station by ranking the subscriber stations by channel strength. Using sequential nullspace methods, the ranked channel matrices are then used to select the channel matrix Hi for the best subscriber station, to design the wi, vi for the best subscriber station as the left and right singular vectors of the MIMO channel matrix Hi, to transform the remaining channels and to continue the process until beamforming vectors are designed for all channels.

The present invention provides an antenna-array-based multiple-input multiple-output orthogonal-frequency-division-multiplexing (MIMO-OFDM) system and a pre-coding and feedback method used in the same. The present invention uses QR decompositions of the MIMO channel matrixes to parameterize the channel state information (CSI) of every OFDM frequency band. In addition, the present invention feeds back the information related to θ and φ in the Givens rotation matrixes of the partial frequency bands and then uses an interpolation method to generate θ and φ in the Givens rotation matrixes of all the frequency bands, which further is able to represent the CSI of all the frequency bands. In this way, the present invention has advantages of low complexity and low feedback rate requirement.

Provided is a MIMO-OFDM system codebook search based reducing procode feedback information bit number method and device which is used in the air interface communication between users and the base station. The users include the channel state information acquisition unit and a channel variation tracing unit. According to the channel state information, the corresponding largest singular values of MIMO channel matrix are extracted from each OFDM sub channel and according to the sequence of OFDM sub channel, the largest singular values can be viewed as points on a smooth curve and the pole can be found. The codebook search unit searches the complete codebook to the sub channel corresponding to the pole and obtains the corresponding complete codebook procode vector serial number. The sub channeles which ar not corresponded to the pole are divided into a number of groups according to the sequence of OFDM channel, and the construction and searching methods of sub codebook are used to obtain the procode codebook vector sub codebook serial number for each group of sub channels which are not corresponded to the pole. The feedback information integration unit feedbacks the series of codebook vector serial number information to the transmitting end.

The invention discloses a transmitting antenna selection method for a generalized spatial modulation system under a correlated channel. The method comprises the following steps that 1) a receiving terminal performs ideal channel estimation to obtain an NR*MT MIMO (multiple-input and multiple-output) channel matrix H of the generalized spatial modulation system; 2) the receiving terminal calculates an L2 norm measure matrix Fh and a distance measure matrix D, which are used for the antenna selection method, according to the MIMO channel matrix H obtained in the step 1); 3) the receiving terminal selects an effective transmitting antenna set Phi according to the L2 norm measure matrix Fh and the distance measure matrix D, and informs a transmitting terminal of a selection result through a feedback channel; 4) the transmitting terminal performs generalized spatial modulation and transmission according to the effective transmitting antenna set Phi selected in the step 3). According to the method, characteristics of a spatial constellation set are changed by transmitting antenna selection in the generalized spatial modulation system, so that the problem that the bit error rate and capacity performance of the system are greatly reduced due to the fact of spatial constellation distinction difficulty caused by the correlation of transmitting antennae in an actual generalized spatial modulation system is solved.

A modulation identification method under an MIMO related channel based on a machine learning algorithm of the invention belongs to the field of communication. The method comprises the specific steps as follows: first, space-time coding is performed on each data flow of a communication transmitter, and code words are emitted out through Nt transmitting antennas; then, a correlation matrix (as shown in the description) of a receiver and a correlation matrix (as shown in the description) of the transmitter are received, and an MIMO channel matrix H is calculated; the received signal on each receiving antenna is calculated according to the MIMO channel matrix H and corrected; and finally, each receiving antenna extracts the features of the corresponding corrected signal, training test is performed on the extracted feature values, and a modulation identification mode to which a sample belongs is calculated. The advantages are as follows: the method has strong robustness and generalization ability to non-Gaussian channels, and modulation system identification under a more complex environment can be realized through parameter iteration; and by extracting high-order moment and high-order cumulant features, the signal feature difference is obvious under high signal-to-noise ratio, and the classification of a machine learning algorithm is facilitated.

The invention discloses a 3D (three-dimensional) MU-MIMO (multiple user-multiple input multiple output) precoding method based on an orthogonal joint codebook set, and relates to the technical field of mobile communication. The method comprises the following steps of enabling a base station terminal to adopt a uniform surface antenna matrix, and simultaneously store the orthogonal joint codebook set together with a user terminal; according to a 3D MIMO channel matrix, enabling the user terminal to select the optimum precoding vector in the horizontal dimension and the vertical dimension; feeding the corresponding number of the precoding vector back to the base station terminal, enabling the base station terminal to form a 3D precoding matrix, and sending signals to a plurality of users to carry out the 3D precoding processing. The method has the advantages that the orthogonal joint codebook set covers larger space, and the orthogonality is formed between the codebooks, so the matching of the 3D MIMO channel is more accurate and comprehensive, and the interference of MU channel sharing is effectively inhibited; meanwhile, by selecting the optimum precoding matrix, under the condition of not increasing the feedback amount, the channel information in the horizontal dimension and the vertical dimension are comprehensively utilized, and the integral property of the system is improved.

The invention discloses an uplink system resource allocation method based on beam forming; in allocation period, BS can obtain channel state information of each SS uplink in each time slot in a frame by the channel detection technology, and for each SS, the eigenvalue of MIMO channel matrix is decomposed in each time slot. The biggest eigenvalue after decomposition and corresponding eigenvectors form channel power gain matrix of each SS in each time slot; BS utilizes marginal effect and improved greedy algorithm to allocate time slots for each SS; each SS extracts allocated time slot information from a received downlink subframe and allocates power and bit; each SS sends the information of allocated power and bit to BS by a control part of an uplink subframe; BS is used for processing the received data to obtain the original data sent by SS. The invention also discloses a corresponding device, comprising a self-adaptive beam forming, sub-carrier allocation module as well as a power and bit allocation module. The method is of low complexity and good real-time property.

The invention relates to a multi-input and multi-output (MIMO) optical communication system and method. The optical communication system is formed by adopting a plurality of light sources with spectrum differences and a plurality of optical detectors with spectrum response characteristic differences, the spectrum differences of the light sources and the spectrum response differences of the optical detectors ensure that channel impact responses from light sources of all emitters to photoelectric detectors of all receivers are mutually uncorrelated, thus an MIMO channel matrix is obtained, and concentrated MIMO optical communication is realized. According to the invention, MIMO optical communication is realized in an optical fiber channel or free space channel without a complex optical device, thus optical communication rate and reliability are improved.

A sub-matrix is selected from an estimated multiple input, multiple output (MIMO) channel matrix, wherein the estimated MIMO channel matrix is constructed based on a codebook. A singular value decomposition (SVD) is calculated based on the sub-matrix. A steering matrix is calculated based on the SVD and the codebook.

The present invention provides an antenna-array-based multiple-input multiple-output orthogonal-frequency-division-multiplexing (MIMO-OFDM) system and a pre-coding and feedback method used in the same. The present invention uses QR decompositions of the MIMO channel matrixes to parameterize the channel state information (CSI) of every OFDM frequency band. In addition, the present invention feeds back the information related to θ and φ in the Givens rotation matrixes of the partial frequency bands and then uses an interpolation method to generate θ and φ in the Givens rotation matrixes of all the frequency bands, which further is able to represent the CSI of all the frequency bands. In this way, the present invention has advantages of low complexity and low feedback rate requirement.

The invention discloses a visible light communication MIMO (Multiple Input Multiple Output) system giving consideration to positioning. The visible light communication MIMO system comprises a transmitting terminal and a receiver, wherein the transmitting terminal comprises N LEDs (Light-Emitting Diodes); each LED is used for sending a plurality of independent data packets; a data frame at a first preset position of each data packet is a functional frame; each LED sends an optical signal with position information of the LED under equal power in a gap at a position corresponding to a number of the LED; at a position of a second data frame, N LEDs can simultaneously send a channel response training sequence according to a modulation mode and carry out combined channel response estimation; the receiver can obtain an MIMO channel matrix according to distribution of strength of the optical signals sent by the N LEDs and is used for demultiplexing N paths of signals; and meanwhile, the receiver can decode out the LED position information carried in the optical signals so as to implement visible light positioning. The visible light communication MIMO system has the following advantages that the data frames combine positioning of ID (Identity) information and acquisition of the channel matrix; and when visible light positioning is implemented, an effective load proportion in the data frames is improved.

The present invention provides a novel codebook-based multi-base station unite pre-coding scheme. In this invention, multiple cooperating base stations commonly transmit signals to a mobile terminal. The mobile terminal estimates a channel matrix of a unite MIMO channel from the multiple cooperating base stations, and selects the optimal pre-coding matrix index from the pre-coding matrix codebook based on the unite MIMO channel matrix and feeds it back to the multiple cooperating base stations. Each cooperating base station selects the optimal pre-coding matrix based on the received pre-coding matrix index and uses the corresponding portion of the pre-coding matrix to perform unite pre-coding on the data. Namely, the respective partial pre-coding matrixes as employed by all cooperating base stations together form the pre-coding matrix that is optimal to the mobile terminal, and the pre-coding matrix as used by respective cooperating base stations is a part of the optimal pre-coding matrix. By using the codebook-based multi-base station unite pre-coding scheme according to the present invention, the user performance is improved, the complexity of implementation is low, and the demand on network connecting the base stations is very low.

A sphere decoding method applied to a MIMO channel is provided. Multiple constellation points of an nth detection layer corresponding to the MIMO channel matrix are enumerated based on an enumeration rule, and at least one nth sub-set of the nth detection layer is defined. The constellation point with the least PED is obtained as a preferred point. Another constellation, not in the nth sub-set, of the nth detection layer is selected to substitute for the preferred point as one of the nth sub-set. If other preferred points are needed to be obtained, the nth sub-set is updated repeatedly according to the least PED. An optimal solution is determined according to Kn preferred points of the nth detection layer.

The invention discloses a multipoint-multiuser uplink low-complexity MIMO (Multiple Input Multiple Output) detection method which is mainly used for solving the problem that full diversity gain cannot be acquired in the conventional user detection method. The implementation process of the method comprises the following steps of: constructing an interference channel matrix of each user set by a receiving end according to an MIMO channel matrix estimated by a receiver, and searching an orthogonal normalized matrix in a null space of the interference channel matrix to realize separation of signals of different user sets; performing independent MIMO detection on each user set by using a corresponding MIMO detection method according to an encoding mode adopted by a transmitting end to acquire intermediate detection results with partial diversity gain of different users in the same user set; and finally iterating the intermediate detection results to acquire the final detection result with full diversity of each user. The method has the advantages of low overall complexity and capability of acquiring the full receiving diversity gain while realizing separation of the signals of different user sets, and can be used for multipoint-multiuser uplink user detection.

The performance of a Single Code Word (SCW) design with low complexity MMSE receiver & rank prediction is similar to the Multiple Code Word (MCW) design with successive interference cancellation (SIC). A method of rank prediction comprises calculating MIMO channel matrices corresponding to layer transmissions for each tone, calculating signal-to-noise ratios (SNRs) for each tone based on the MIMO channel matrices, mapping the SNR for each tone to generate effective SNRs for each layer transmission, calculating additive white Gaussian noise (AWGN) capacities corresponding to the effective SNRs and maximizing an over-all spectral efficiency based on the AWGN capacities; and selecting a rank based on maximizing the over-all spectral efficiency.

A Process for selecting a Precoding Matrix Index (PMI) in a Multiple In Multiple Out (MIMO) receiver of a wireless communications comprising a base station communicating with User Equipments through a downlink and uplink channel, said base station applying a precoding on the transmit symbol vector based on a matrix Pi being selected from a set of predefined matrices and identified by a PMI index computed by said UE and forwarded to said base station via said uplink; said process involving step of: —estimating (100) the MIMO channel matrix H of a given set of resources blocks comprising received symbol vectors; —estimating (200) the variance σ2 of the additive noise (AWGN)—computing (300) for each particular matrix comprised within said set of predefined matrix a cost function Fi (Pi, H, σ2n) being representative of the orthogonality of said matrix MIMO channel matrix H; —comparing (400) the values of said cost function Fi; and —transmitting (500) to said base station the index i corresponding to the Fi representative of the best conditionned MIMO channel matrix.

A sphere decoding method applied to a MIMO channel is provided. Multiple constellation points of an nth detection layer corresponding to a MIMO channel matrix are enumerated based on an enumeration rule, and at least one nth sub-set of the nth detection layer is defined. The candidate range of the constellation points of the at least one nth sub-set is determined according to a predetermined number K of the preferred points of the at least one nth sub-set. K constellation points are obtained from the at least one nth sub-set as the preferred points according to partial Euclidean distances of the constellation points. The at least one nth sub-set includes at least K constellation points. Kn preferred points are selected from all K preferred points of the at least one nth sub-set. An optimal solution is determined according to the Kn, preferred points.

The invention relates to a user scheduling method for a multiple-user multiple input multiple output (MU-MIMO) system downlink, which comprises the following steps: 1, channel estimation is carried out by users according to a received pilot frequency data so as to acquire the current multiple input multiple output (MIMO) channel matrix of each user, each user respectively calculates a Frobenius numerical value of the MIMO channel matrix of the user, namely the MIMO channel gain of the user; 2, a base station acquires the MIMO channel matrix and the MIMO channel grain of each user side throughchannel reciprocity; 3, the base station schedules the user having the maximum MIMO channel grain as the first user to which the base station transmits according to the MIMO channel grain acquired from the users; and 4, the base station substitutes the MIMO channel matrixes of the scheduled user and the user not to be scheduled to a user scheduling function, calculates and selects the user corresponding to the maximum function value as the next scheduling user, and traverses all the users not be scheduled in sequence until the number of scheduled users reaches the design requirement of a basestation scheduler. The invention has the beneficial effects that the throughput of the MU-MIMO system is improved.

The invention belongs to the technical field of MIMO communication, and particularly relates to an improved SVD precoding algorithm for MIMO-OFDM under the background of a frequency domain selective fading channel. The core of the method is to optimize the SVD decomposition of ab MIMO channel matrix under each subcarrier so as to prevent the traditional precoding matrix based on SVD decompositionfrom damaging the smoothness of the channel in the frequency domain. The invention provides a modeling method for quantifying channel smoothness, and designs and improves an algorithm of an SVD precoding matrix. An optimization simulation result shows that the algorithm can significantly improve the smoothness of the equivalent channel in the MIMO-OFDM system in the frequency domain, and is beneficial to channel estimation.

The invention discloses a three-cell blind interference suppression method based on energy efficiency priority. All base stations of three cells adopt different data transmission schemes, and two of the base stations use a part of antennas for switching transmission; according to the same antenna and by utilizing the transmission characteristic that signals at adjacent transmission moments in a slowly changing channel have high correlation, interference can be removed under the condition that a transmitting end does not know any MIMO channel matrix information disturbing users and data information disturbing the users by means of performing corresponding receiving processing at a receiving end. The three-cell blind interference suppression method based on energy efficiency priority is used for three adjacent cells, and lowers circuit energy consumption of a feedback link by removing the feedback link under the condition of guaranteeing that transmission error codes are within an acceptable range, thereby improving system energy efficiency.

The invention provides a terahertz MIMO channel modeling method and system based on measured data. The method comprises the following steps: calculating a diffraction limit resolution of an optical system based on center frequency of a to-be-measured terahertz frequency band, a preset communication distance between a transmitting end and a receiving end, and the number of virtual antennas of the receiving end, so that distances between adjacent transmitting antennas in a transmitting end antenna array of an MIMO channel model and distances between adjacent receiving antennas in a receiving end antenna array of the MIMO channel model are determined; using single-input single-output channel test equipment to test sight distance channel frequency response between each transmitting antenna of the transmitting end and each array unit of the receiving end for several times, so that a measured MIMO channel matrix is obtained; obtaining a performance parameter index of an MIMO channel based on the measured MIMO channel matrix; calculating channel impact response based on the MIMO channel matrix, and obtaining time-frequency relevance of adjacent channels based on the channel impact response; and obtaining channel path loss based on the time-frequency relevance, and obtaining a frequency selectivity result of a terahertz channel based on the channel path loss.

The invention discloses an antenna selection method of a large-scale MIMO system, belonging to the technical field of wireless communication. The method comprises the following steps: (1) initializingtwo empty antenna selection subsets S, T; (2) calculating the norm of each column in the large-scale MIMO channel matrix H, placing the column with the largest norm in the antenna selection subset Sas the reference antenna for the next antenna selection, and deleting the column and the column with the smallest norm from the matrix H to update the matrix; (3) traversing the remaining antennas ofthe matrix H, placing the column with the least correlation in the antenna selection subset S as a new reference antenna, and simultaneously deleting the column and the column with the greatest correlation from the matrix H to update the matrix; (4) selecting a specified number of antenna array sets; (5) computing the capacity and energy efficiency of large-scale MIMO system. The invention reducesthe deployment of the radio frequency link, reduces the hardware cost and the realization complexity, and improves the system capacity and the energy efficiency without increasing the computational complexity through the bidirectional cross iteration selection of the channel matrix of the large-scale MIMO system.

Channel state information for closed-loop transmit precoding in MIMO networks is fed back from the MSs to the BSs. The feedback is quantized using codebooks shared by the MSs and BSs to reduce overhead. The codebooks can be full-rank or rank-one. The quantized feedback is applicable to any definitions of MIMO channel covariance matrix as well as MIMO channel matrix. Since these codebooks are designed for closed-loop MIMO precoded transmissions, no additional memory is needed to store the codebooks at the BS and the MS only for the quantized feedback purposes.

The invention discloses a wireless channel measuring data analyzing method based on dual-polarized MIMO (Multiple-Input Multiple-Output). The data of wireless channels in a specific scene are measured by a wireless channel detector; dynamic threshold value interception is carried out to the measuring data by MATLAB software; a valid dynamic interval is obtained; the influence of cross polarization is eliminated; after the valid dynamic interval of the measuring data is obtained, polarization separation is carried out to the data in the valid dynamic interval; horizontal-polarized, vertical-polarized and dual-polarized MIMO channel matrixes are obtained; channel parameters are calculated through a preset algorithm; the features of the dual-polarized MIMO channels in the specific scene are analyzed; therefore, the features of the dual-polarized MIMO channels in different scenes are researched rapidly; and the method has important significance in modeling the dual-polarized MIMO channels.

A process selects a Precoding Matrix Index (PMI) in a Multiple In Multiple Out (MIMO) receiver used in a wireless communications system including a base station communicating with User Equipments (UE) through a downlink and uplink channel. The base station applies a precoding on the transmit symbol vector based on a matrix selected from a set of predefined matrices and identified by a PMI index computed by the UE and forwarded to the base station via the uplink. The process includes estimating the MIMO channel matrix H of a given set of resources blocks comprising received symbol vectors, estimating the variance σ2 of the additive noise (AWGN), and computing for each particular matrix comprised within the set of predefined matrices a cost function representative of the orthogonality of the matrix MIMO channel matrix H. The process further includes comparing the values of the cost function and transmitting to the base station the index corresponding to the matrix corresponding to the best conditioned MIMO channel matrix according to the comparison of the values.

The invention discloses a codebook generating method of pre-coding in a multiple-input-multiple-output (MIMO) system, which comprises the following steps: carrying out geometric mean decomposition (GMD) on an MIMO channel matrix to acquire a pre-coding matrix V to be quantized; acquiring a probability distribution function p(V) of the pre-coding matrix V to be quantized by the transmission channel matrix of the MIMO; acquiring the mean quantization error of the system according to the pre-coding matrix V and the probability distribution function p(V) thereof; and acquiring a codebook matrix according to the mean quantization error of the system. The invention also provides a codebook generating device corresponding to the method, which comprises a computing module, an acquiring module and a codebook generating module. The codebook matrix generating method provided by the invention is matched with the channel matrix, thereby being suitable for various channel conditions; and for an MIMO pre-coding system of which the receiver adopts a vertical stratification method, the method of the invention can obtain better performance promotion.

The invention discloses a sphere decoding method applied to a multi-input multi-output (MIMO) channel, which comprises the following steps: arranging a plurality of starlike points of an nth estimation layer by an enumeration method and according to the nth estimation layer corresponding to a matrix of the MIMO channel, and defining at least one nth subset of the nth estimation layer; taking a starlike point with the minimum part of Euclidean distance (PED) serving as a better point out from a nth subset according to the PED; selecting another starlike point of the nth estimation layer except the nth subset according to the better point, and replacing the better point with the another starlike point serving as one member of the nth subset; if other better points need to be found, repeating the second step according to the minimum PED and updating the nth subset; and determining an optimal solution according to Kn better points of the nth estimation layer.

The invention discloses a data transmission method and a data transmission device based on SM-MIMO. The data transmission method comprises steps that a null space matrix is determined by singular value decomposition of an MIMO channel matrix on a receiving end; an interference signal is determined according to the null space matrix, a corresponding weight vector, and a random signal; and by adopting the SM technology, the interference signal and a to-be-transmitted signal are transmitted. The interference signal is added to the to-be-transmitted signal, and the interference signal is determined according to the MIMO channel matrix singular value decomposition from a transmitting end to the receiving end, and therefore no interference on the receiving end is caused by the interference signal, and an eavesdropper is affected by the interference signal, and the safety speed of the receiving end is improved, and in addition, the safety of the data transmitted to the receiving end is guaranteed.

The invention discloses an MIMO DCO-OFDM (multiple-input multiple-output direct-current-biased optical orthogonal frequency division multiplexing) communication method. The method includes: aiming at clipping noise generated by clipping operation of a sending end, creating a whitening filter at a receiving end according to a linearization model of the clipping operation of the sending end and statistical characteristics of the clipping noise, and utilizing the whitening filter to filter receiving signals on each sub-carrier and an equivalent wireless light MIMO channel matrix acquired by estimation respectively; utilizing the equivalent wireless light MIMO channel matrix after being filtered to restore the receiving signals after being filtered. The invention further discloses an MIMO DCO-OFDM signal receiving device and an MIMO DCO-OFDM communication system. Compared with the prior art, the MIMO DCO-OFDM communication method has the advantages that remarkable bit error rate performance gain can be acquired, and easiness in engineering realization is realized.