A wireless communication system including receiving and base stations. The receiving station includes a detector that measures a downlink channel correlation matrix for multiple antennas of a base station. The detector computes an antenna weight increment vector normal to an antenna weight vector for multiple beams from the multiple antennas of the base station. The detector quantizes the antenna weight increment vectors to produce a respective quantized antenna weight increment vector. The receiving station includes a transmitter that sends the quantized antenna weight increment vectors to the base station. The base station includes a beamformer selector that receives from the receiving station and re-orthogonalizes the quantized antenna weight increment vector for each of the multiple beams. The base station includes a weight vector modifier that modifies the antenna weight vector for the multiple beams by adding an increment proportional to the respective re-orthogonalized quantized antenna weight increment vector.
Adaptive precoding codebooks are described. In one embodiment, the method of wireless communication includes reading at least a rank-2 baseline codebook having codewords representing precoding matrices. An adaptive codebook is generated by multiplying a first column of the codeword with a first transform matrix calculated from a channel correlation matrix, and multiplying a second column of the codeword with a second transform matrix calculated from the channel correlation matrix. The first and the second transform matrices are orthogonal.
A high-order Multiple-Input-Multiple-Output (MIMO) transmitter implementing a covariance-based precoding scheme that exploits transmit channel correlation and a method of operation thereof are provided. In one embodiment, covariance-based precoding is performed at the high-order MIMOtransmitter based on feedback from a remote high-order MIMOreceiver regarding a covariance-based precoding matrix. The covariance-based precoding matrix is, or is derived from, a transmit channel correlation matrix determined by the high-order MIMO receiver for the high-order MIMO transmitter. The covariance-based precoding provides a beam-forming effect when there is a relatively high degree of transmit channel correlation, thereby improving performance of the high-order MIMO transmitter. Further, because changes in the transmit channel correlation occur relatively slowly over time, feedback overhead requirements are substantially reduced as compared to that required for traditional MIMO precoding schemes.
A code division multiple accessuser equipment is used in receiving a plurality of data signals over a shared spectrum. Each received data signal experiences a similar channel response. A combined signal of the received data signals is received over the shared spectrum. The combined signal is sampled at a multiple of the chip rate. A channel response is estimated. A column of a channel correlation matrix is determined using the estimated channel response. A spread data vector is determined using the determined column, the estimated channel response, the received combined signal and a fourier transform. Data of the data signals is estimated using the spread data vector.
The invention discloses a method, a system and a device for selecting a precoding vector and a mobile terminal. The method for selecting the precoding vector comprises that: a receiving end performs quantization treatment on a channel correlation matrix according to the stored vector quantizationcodebook aiming at the channel correlation matrix; the receiving end feeds back the information of the channel correlation matrix subjected to the quantization treatment to a transmitting end; and the transmitting end acquires the channel correlation matrix according to the stored vector quantizationcodebook aiming at the channel correlation matrix and the received information subjected to the quantization treatment, and selects the precoding vector according to the acquired channel correlation matrix. Due to the technical scheme, the amount of the quantization information fed back by the receiving end is reduced, and the amount of the quantization information fed back by the receiving end is not increased along the increase of the antenna amount of the receiving end.
A wireless communication system including receiving and base stations. The receiving station includes a detector that measures a downlink channel correlation matrix for multiple antennas of a base station. The detector computes an antenna weight increment vector normal to an antenna weight vector for multiple beams from the multiple antennas of the base station. The detector quantizes the antenna weight increment vectors to produce a respective quantized antenna weight increment vector. The receiving station includes a transmitter that sends the quantized antenna weight increment vectors to the base station. The base station includes a beamformer selector that receives from the receiving station and re-orthogonalizes the quantized antenna weight increment vector for each of the multiple beams. The base station includes a weight vector modifier that modifies the antenna weight vector for the multiple beams by adding an increment proportional to the respective re-orthogonalized quantized antenna weight increment vector.
The invention discloses a channel correlation-based user group partition method under D2D. The method comprises the following steps: (1) enabling users to measure a pilot frequency transmitted by a base station, and feeding back channel correlation matrixes and receiving signal intensities by means of an uplink; (2) obtaining the estimated positions of all the users according to an MUSIC (multiple-signal-classification) method and an RSS (receive-signal-strength) method, and adopting a binary group to indicate user positions; (3) carrying out clustering processing on the user by using a K-means method. The user group partition method provided by the invention can complete the partition of a two-step pre-coded user group of a cellular network and the discovery of a D2D cluster at the same time by utilizing cellular channel correlation matrix information, thus avoiding a complicated operation of directly utilizing channel correlation information to process medium and high-dimension matrix subspace division and projection; the method has the characteristics of being simple and efficient.
A high-order Multiple-Input-Multiple-Output (MIMO) transmitter implementing a covariance-based precoding scheme that exploits transmit channel correlation and a method of operation thereof are provided. In one embodiment, covariance-based precoding is performed at the high-order MIMOtransmitter based on feedback from a remote high-order MIMOreceiver regarding a covariance-based precoding matrix. The covariance-based precoding matrix is, or is derived from, a transmit channel correlation matrix determined by the high-order MIMO receiver for the high-order MIMO transmitter. The covariance-based precoding provides a beam-forming effect when there is a relatively high degree of transmit channel correlation, thereby improving performance of the high-order MIMO transmitter. Further, because changes in the transmit channel correlation occur relatively slowly over time, feedback overhead requirements are substantially reduced as compared to that required for traditional MIMO precoding schemes.
The invention discloses a low complexity channel estimation method in a large scale MIMOsystem. The method comprises the following steps of firstly, establishing an optimization estimation problem of a channel covariance matrix; and secondly, according to an iteration relation of covarianceestimation, using a Sherman-Morrison theorem to convert matrix inversion into a matrix and vector product form so that a method complexity is reduced. In the method, approximation estimation is performed on a channel correlation matrix and the Sherman-Morrison theorem is used to convert the matrix inversion in a MMSE method into the matrix and vector product so that a calculating complexity in the MMSE method is greatly reduced and a low performance loss is possessed.
The invention discloses a method for judging the mode of down space division multiple access of a time division duplex system, which includes the steps: the operation of channel estimation is carried out to a special physical channel for up adjoint to obtain the channel impulse response matrix of each user; the normalized spatial correlation matrix of each user is calculated; the eigenvalue of each spatial channel correlation matrix is analyzed so as to gather out and take the corresponding eigenvector of each eigenvalue of maximum as the forming weight of each user; the spatial correlation measure of every two users is calculated according to the forming weight of each user; and any user and the user with the spatial correlation measure less than a preset value are classified into the same set, and the actuating codes of the users in the same set are multiplexed by the mode of space division multiple access. The method can judge whether the users can adopt the SDMA mode to carry out the operation of data down-load or not according to the space division properties of the users, and the TDD HSDPA system can effectively utilize spatial information to increase the throughput of data transmission of the system and can increase the capacity of the system.
The embodiment of the disclosure provides a channel feedback method and device based on hybridbeamforming. The method comprises the following steps: estimating a physical channel correlation matrix of a long-time broadband; feeding back the physical channel correlation matrix of the long-time broadband to a base station; estimating a short-time narrow-band equivalent channel after analog beamforming; and feeding back the short-time narrow-band equivalent channel to the base station based on an adaptive codebook. The embodiment of the disclosure also provides a corresponding channel feedback method and a corresponding device. According to the channel feedback solution based on hybridbeamforming provided by the embodiment of the disclosure, the feedback overhead can be significantly reduced, the number of RF channels in the system can be reduced, and the system performance which is better than a traditional pure digital beamforming scheme can be obtained with the same feedback overhead.
The invention discloses a method for determining a valid signal-to-noise ratio, comprising the following steps of: in an OFDM (orthogonal frequency division multiplexing) system, determining a channel correlationmatrix estimation value of a measured bandwidth according to the channel estimation result of a time frequency sub-channel at a pilot frequency position in the measured bandwidth; respectively calculating channel capacity of the time frequency sub-channel of each interference type of the measured bandwidth by using the channel correlationmatrix estimation value; obtaining an average equivalent channel capacity of each time frequency sub-channel on the measured bandwidth according to the channel capacity of the time frequency sub-channel of each interference type; and determining the valid signal-to-noise ratio of the measured bandwidth according to the average equivalent channel capacity of each time frequency sub-channel. The invention further discloses a device for determining a valid signal-to-noise ratio. With the method and the device provided by the invention, computational complexity for the valid signal-to-noise ratio can be reduced.
An apparatus and method of applying a superfast algorithm to a pilot-based channel estimation process includes receiving a signal comprising information bits transmitted in a wireless channel, executing the pilot-based channel estimation process having p structures for a vector of pilot structures and an upper bound N for a channel spread, determining a result of a matrix inversion of a channel correlation matrix for an error channel estimation offline without performing a matrix inversion, storing pilot information of the received signal for channel recovery in a transform domain, representing the Toeplitz inverse by a FFT representation, detecting and estimating nonzero taps of a channel impulse response of the wireless channel, obtaining a non-structured minimum mean-square-error (MMSE) estimate as a first estimate of locations of the nonzero taps, and replacing the non-structured MMSE estimate by an estimate computed by a tap detection algorithm.
The invention discloses a multi-antenna diversity combination receiving method and a device. The method is characterized in that the diversity combination step is carried out in the associated detection in advance, that is to say that diversity combination is carried out after completing matched filtering of each antenna data and calculating the channel correlation matrix corresponding to each antenna in associated detection process; and decomposition and linear equation resolving are carried out according to the combined channel correlation matrix and the combined matched filtering result to obtain a sign to be demodulated, thereby obviating the operations of decomposition and linear equation resolving for each antenna according to the matched filtering result and the channel correlation matrix of each antenna. The multi-antenna diversity combination receiving method provided by the embodiment has better diversity gain in comparison with single antenna receiving, and can remarkably reduce the calculation amount and the realization complexity of the system in comparison with the existing diversity combination receiving system under the condition of same diversity gain performance.
The invention discloses a beam forming method for a compact planar array Massive MIMOsystem. The beam forming method comprises the following steps: constructing a high-frequency sparse channel model on the basis of not considering a mutual coupling effect; performing asymptotic analysis on the high-frequency sparse channel model to obtain an asymptotic equivalence formula of a channel correlation matrix; based on an asymptotic equivalence formula, establishing an optimization model by taking maximization of the minimum receiving SINR values of all users as a target; carrying out equivalent transformation and solving on the optimization model to obtain a beam forming weight vector; based on the beamforming weight vector, performing beamformingprocessing on the user data, and performing signal transmission. According to the method, an asymptotic equivalence formula of a channel correlation matrix is derived through asymptotic analysis of a high-frequency sparse channel, and on the basis, a beamformingoptimization problem is established by taking maximization of a user receiving signal to interference plus noise ratio as a target, so that the robustness of system performance to mutual coupling damage is ensured while the user sum rate is improved.
The embodiment of the invention discloses a technical scheme of a grouping decoding method based on partial interference elimination and a receiver. The grouping decoding method based on partial interference elimination comprises the following steps: carrying out triangular decomposition on a correlation matrix of a channel, inverting the decomposed matrix, extracting a submatrix related to a group of signals from the inverted matrix aiming at each group of which the transmitting signals are divided into, acquiring a receiptsignal vector and an equivalent channel matrix corresponding to the group after between-group interference is eliminated according to the matrix after orthogonal decomposition of the submatrix, and detecting the transmission vector of the group of the signals by utilizing a multiple input and multiple output detection method according to the receiptsignal vector and the equivalent channel matrix corresponding to the group after the between-group interference is eliminated. The technical scheme lowers the realization complexity of grouping decoding and saves the processing resources of the receiver.
A method and apparatus for performing chip level equalization (CLE) using joint processing to enhance performance and systemthroughput using a transmitter having a plurality of transmit antennas and a receiver having a plurality of receive antennas. A channel response matrix is formed between the transmit antennas and the receive antennas to generate a joint channel correlation matrix between the transmit antennas and the receive antennas using a block-FFT (B-FFT) decomposition of the channel response matrix. Estimates of transmitted chip sequences from each of the transmit antennas are generated using minimum mean square error (MMSE) and the joint channel correlation matrix are combined. The combined estimate of the transmitted chip sequences are despread to recover transmitted data.