55 results about "Mimo detector" patented technology

A method and system for detecting and decoding multiple signals. A low-complexity MIMO detector that combines sphere decoding and m-algorithm approaches, while accounting for the effect of channel condition on the decoding operation, is provided. Taking into account the channel condition effectively controls the size of the search tree, and consequently the search complexity, in an adaptive manner. The channel condition is exploited in the construction of the tree to manage the number of branches in the tree and to avoid undesirable growth.

The performance of multiple-input multiple-output (MIMO) systems, employing coding with multiple antennas depends heavily on the demapper algorithm which is used for MIMO detection. Soft-output demappers lead to better bit error rate (BER) performance compared to hard-decision demappers, but have a higher implementation complexity. The algorithm, proposed in this paper, relies on low-complexity harddecision MIMO detection. The reliability information for the received bits used to compute log-likelihood ratios is based on an estimate of the average bit error rate which is for example derived from the corresponding channel state information only. The algorithm is applicable to any hard-decision MIMO detector. As an example, we describe the application of the scheme to a linear MMSE detector and to sphere decoding with early termination.

A scalable Multiple-Input Multiple-Output (MIMO) detector, comprises an ordering block, a group interference suppression block, a core detector and a residual detector. The ordering block determines an order of the columns of a channel matrix including received streams based on the power thereof. The group interference suppression block coupled to the ordering block groups received streams into a core part and a residual part, the core part including a first received stream and a second received stream corresponding to the first two columns of the channel matrix in the order, the first received stream and the second received stream forming a received signal vector, and the residual part including the rest of the received streams. The core detector detects the core part based on a 2×2 Simplified Maximum Likelihood (SML) detection. The residual detector detects the residual part by Vertical Bell Laboratories Layered Space Time (VBLAST) detection.

A Lenstra-Lenstra-Lovász (LLL)-based technique is utilized to reduce the complexity of a MIMO detector. Basis vectors can be pre-sorted, such as by V-BLAST ordering or sorted-QR ordering, prior to applying Gram-Schmidt Orthogonalization (GSO) to further improve performance. Alternatively, a joint sorting and LLL reduction (JSAR) technique can be utilized such that after each reduction step, a vector remaining to be reduced can be selected that will minimize the overall complexity. The JSAR technique can be applied on real or complex lattice bases. LLL reduction can be stopped after a predetermined threshold is exceeded.

The present invention relates to the fields of precoded spatial multiplexing MIMO communication systems, especially to the subject of selecting precoding matrices. The present invention especially relates to a communication device, a communication method and a software program product. The MIMO communication device according to the present invention comprises a memory for storing a plurality of MIMO precoding matrices realizing the transmission side encoding of an Eigenbeamforming system; a controller for calculating, for each of at least some of the stored precoding matrices, an indicator value of the SNR of at least one decoupled transmission channel based on at least part of the corresponding precoding matrix, and for selecting one of said stored precoding matrices based on said calculated at least one indicator value of the SNR; and a MIMO detector for detecting symbols based on said selected precoding matrix. Because selection of the precoding matrices is based on SNR indicator values, the SNR can be optimized which is resulting in a higher data rate. Moreover, no computationally complex calculation of a SVD is required for the precoding matrix selection according to the present invention.

A method and a communication receiver have been described for calculating log-likelihood ratios in a communication receiver. The log-likelihood ratio is calculated for each bit of one or more subsymbols of each of the one or more spatial streams by computing effective noise on one or more spatial streams after considering noise terms resulting from MIMO detection estimates of the subsymbols on each spatial stream. Finally, signal to noise ratio is determined for one or more spatial streams from the effective noise and scaling bit log-likelihood ratios with the signal to noise ratio.

The invention discloses a distributed detection method of a large-scale multiuser MIMO system. The method comprises the following steps: dividing received signals into multiple groups, performing distributed signal detection on each group of received signals by using an MIMO signal detection module based on an EP algorithm, and then adopting different processing processes on three EP MIMO detectors to obtain a final detection result. According to the distributed detection method disclosed by the invention, the application complexity of the EP algorithm in the signal detection of the large-scale multiuser MIMO system is greatly reduced by a distributed design, the three distributed MIMO detectors based on the EP algorithm have excellent performance in the large-scale multiuser MIMO system,and the distributed detection method can be implemented in terms of complexity.

In a MIMO detector, a slicing list detection scheme employs a complex plane to represent symbols in an alphabet, in which all decision regions are bounded by either vertical lines or horizontal lines. A K-best scheme accesses the complex plane and an offline-generated lookup table to detect elements of a received vector. At each level, the system prunes all but the K-best candidates from each surviving node through the slicing list detector.

A method, system, and apparatus are provided for computing soft bits in a non-linear MIMO detector which decodes a signal received at a plurality of receive antennas using channel estimate information and a decoding tree to produce output data for a bit estimation value which includes a maximum likelihood solution along with a naturally ordered vector identifying all explored node metrics and node indices, where soft bits are computed for each bit estimation value by determining a set of bit-masks through repetition and indexing operations applied on the explored node indices, masking the naturally ordered vector with the set of bit-masks to generate masked node metrics, determining candidate soft bit values by subtracting metrics of all nodes that form the maximum likelihood solution from the masked node metrics, and determining a final soft bit value by identifying which of the candidate soft bit values has a lowest value.

The present invention discloses an integrated gamma spectrum measurement system suitable for neutron activation analysis, which includes a detector, a header multichannel pulse amplitude analyzer, aninterface and a shell. The detector includes a scintillator and a photomultiplier; and gamma ray enters the detector and is finally converted into an electric pulse signal. The header multichannel pulse amplitude analyzer is packaged by the metal shell, which includes a voltage divider circuit, an adjustable high voltage power circuit and a multichannel spectrum acquisition circuit. The voltage divider circuit and the adjustable high voltage power circuit provide the bias voltage for each dynode of the photomultiplier. The multichannel spectrum acquisition circuit realizes the conversion of the ray pulse signal to the spectrum. An interface circuit adopts a PoE interface, which can not only supply power for the system but also realize the function of network port communication. The shell plays a role of carrying, electromagnetic shielding and radiation shielding; and all components and circuits are enclosed in the detector shell. The invention provides the gamma spectrum measurement system with small volume, low cost, convenient application, a high counting pass rate and high energy resolution.

Systems and methods are disclosed that may detect data transmitted using MIMO communications. Data may be received, on a wireless channel, as a plurality of spatial streams. A channel matrix characterizing the wireless channel may also be received. The channel matrix may be decomposed into a first sub-channel matrix and a second sub-channel matrix, each having a lower dimension than the channel matrix. A first estimated data signal may be generated based at least in part on the plurality of spatial streams and the first sub-channel matrix. A second estimated data signal may be generated based at least in part on the plurality of spatial streams and the second sub-channel matrix. The first and second estimated data signals may be combined to recover the data.

The invention relates to a joint list detection and decoding method for fixing the complexity of a multiple input multiple output (MIMO) wireless communication system adopting block codes. The method comprises the following steps of: producing a candidate input code word list of a channel decoder from a candidate list of an MIMO detector by using a list generator so as to avoid iterative processing of a conventional detection and decoding algorithm; replacing soft decoding by hard decoding to reduce the working complexity of a receiving end; and joint processing is performed by using the list generator and the encoder to realize a uniform candidate character sequence space structure under joint constraint of an MIMO signal space and a code word space so as to improve system performance. The invention provides a new joint detection and decoding processing technical scheme which is used for the receiving end and designed by adopting the block codes in a channel coding scheme in the MIMO system. The method reduces calculation complexity and improves detection performance.