69results about How to "Improve error performance" patented technology

A system and method for adapting code rate are provided. A method for a first communication device to transmit a resource assignment to at least one communication device includes assigning at least one transmission resource to transmit the resource assignment, adapting a code rate of an encoded payload based on the at least one transmission resource and a threshold, thereby producing an adapted payload, and transmitting the adapted payload.

An Orthogonal Frequency Division Multiplexing (OFDM) communiation system and method for improving frequency utilization efficiency. In the system, a Reed-Solomon encoder codes input information data, and ouputs a Reed-Solomon block having a second number of Reed-Solomon symbols, each Reed-Solomon symbol having a first number of Reed-Solomon symbol elements. An interleaver receives the Reed-Solomon block, and disperses the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel position in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols.

A diversity transmission scheme uses a number of antennas that is greater than the limitation of two transmitting antennas in the well-known Alamouti scheme. In an embodiment comprising four antennas, the antennas transmit in pairs such that each antenna transmits a block that is used in the Alamouti scheme. This increases the transmission rate. For example, the transmission of two signals at a given time slot increases transmission rate by a factor of two. The invention not only increases the number of antennas, but also increases the transmission rate. At the receiver end, the code is decoded without matrix inversion and without much noise enhancement. Moreover, noise enhancement stability is increased by a simple, partial interference cancellation scheme, that results in improved decoding performance.

A multi-level encoded signal is encoded according to at least an upper-level code and a lower-level code. In a receiver, a modified type of a multistage decoder is deployed. The upper-level code is decoded to produce a sequence of tentative upper-level coding decisions independently of the lower-level code. The lower-level code is next decoded in such a way that the decoding is conditioned upon at least one of the tentative upper-level decisions. The lower-level decoder thereby produces a sequence of lower-level decisions. The upper-level code is then decoded a second time, this time conditioned upon at least one of the lower-level decisions, to produce a second, more reliable sequence of upper-level coding decisions. The lower-level decision sequence and the second upper-level decision sequence are delivered from the decoder as output sequences.

A method for generating candidate used in TCOFDM (turbo coded orthogonal frequency-division multiplexing) with SLM (selective mapping) technique, a user data is combined with a plurality of seeds to generate corresponding a plurality of message vectors. The method is characterized in performing tail-biting turbo encoding on the message vectors to generate corresponding turbo codewords used for generating candidates, and the seed of each message vector is different from the seeds of other message vectors.

An orthogonal frequency division multiplexing (OFDM) communication system and method for improving frequency utilization efficiency. In the system, a Reed-Solomon encoder codes input information data, and outputs a Reed-Solomon block having a second number of Reed-Solomon symbols each having a first number of Reed-Solomon symbol elements. An interleaver receives the Reed-Solomon block, and disperses the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel positions in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols.

The invention provides a project recommendation method and device. According to recorded grading objects and scores thereof to projects, the score mean value of the grading objects to the projects and the types of all projects are determined firstly; then the score mean value of the grading objects to the project types is counted; first related objects with similar type preferences are determined from target objects; then second related objects with similar project preferences are found out from the first related objects; the eligible projects are extracted from the projects which are not graded by the target objects and recommended to the target objects. According to the embodiment of the invention, users with related preferred projects and types are selected out and invalid information not interested by the users are removed by using the interest degrees of the users to different types of projects; all effective information is used when the similarity among the users is calculated, so that the similarity calculation is more accurate, the accuracy of calculating the similarity among the users can be effectively enhanced, and the recommendation quality of a recommendation system is effectively improved.

A method and system are described for adaptively adjusting data communication of a rateless coding system, including adaptively estimating a symbol coding length, determining a symbol threshold, determining if the adaptively estimated symbol coding length is less than the symbol threshold, adjusting a transmission power level based on the second determining act and adaptively adjusting a modulation scheme based on the second determining act. Also described are a method and system for decoding communication of a rateless coding system, including receiving encoded symbols, determining if a length of the received encoded symbols is greater than a threshold number of encoded symbols and decoding the received encoded symbols if the length of the received encoded symbols is greater than the threshold number of encoded symbols.

Methods and apparatus are provided for reading and writing data in q-level cells of solid-state memory, where q>2. Input data is encoded into codewords having N qary symbols, wherein the symbols of each codeword satisfy a single-parity-check condition. Each symbol is written in a respective cell of the solid state memory by setting the cell to a level dependent on the qary value of the symbol. Memory cells are read to obtain read signals corresponding to respective codewords. The codewords corresponding to respective read signals are detected by relating the read signals to a predetermined set of N-symbol vectors of one of which each possible codeword is a permutation.

The optimal power allocation method for an LSSTC wireless transmission system utilizes Layered Steered Space-Time Codes (LSSTC), a recently proposed multiple-input multiple-output (MIMO) system that combines the benefits of vertical Bell Labs space-time (V-BLAST) scheme, space-time block codes (STBC), and beamforming. A new downlink scheme employs LSSTC with optimal power allocation based on the assumption that the user feeds the base station (BS) with the average signal-to-noise ratio (SNR) per V-BLAST layer through the uplink feedback channel. Such a system enhances the error performance by assigning power to the layers in an optimum manner.

The invention discloses a method and system for reducing a peak-to-average power ratio of an OFDM system based on three-dimensional signal insertion. Based on a traditional DSI method, a process of inserting three-dimensional signals into OFDM signal sub-carriers instead of inserting a traditional virtual sequence that does not include information is proposed, each three-dimensional signal occupies two sub-carriers, and compared with the traditional DSI method, the data transmission efficiency is not reduced. Since a three-dimensional signal constellation diagram provides a greater degree of search freedom, the peak-to-average power ratio of the OFDM system can be more effectively improved under the same search complexity and system data transmission efficiency, and no sideband informationneeds to be transmitted. In addition, compared with the mode of inserting two-dimensional signals, without changing the average power of transmitted OFDM signals, the three-dimensional signal constellation diagram has a larger minimum Euclidean distance, and thus the error performance of the system can also be improved to a certain extent.

This present invention relates to a device for the measurement of the amount of oxygen in a gas mixture, or other gas with significantly different magnetic susceptibility than the background gas mixture, by the use of a suspended test body in a magnetic field that experiences force due to the magnetic susceptibility of the measurand gas. In order to enable a fast time response for the system with a change in oxygen concentration, a flow regime is presented which allows a fast sweep of the measurement volume combined with adjustable, balanced pressure drops via a flow balancing element (or elements) within the flow channels to independently minimise flow related uncertainties.

The invention discloses a method and apparatus for decreasing a peak-to-average power ratio of a three-dimensional coherent optical orthogonal frequency division multiplexing system. The method comprises the following steps: (1) converting a binary sequence to obtain a subcarrier index signal; (2) mapping to obtain a frequency-domain orthogonal frequency division multiplexing signal of 3N real-form subcarrier components; (3) recombining to obtain a frequency-domain orthogonal frequency division multiplexing signal of 2N plural-form subcarrier components; (4) modulating the orthogonal frequency division multiplexing signal from the frequency domain to a time domain; (5) introducing a K sequence from the frequency domain, performing zero padding, and superimposing with the time-frequency orthogonal frequency division multiplexing signal after the modulation; (6) searching a K sequence combination with a minimum signal peak-to-average power ratio; (7) dividing the time-domain orthogonal frequency division multiplexing signal into a real-number portion and an imaginary-number portion corresponding to the real-number portion, and converting to an optical signal; and (8) transmitting the optical signal. By adopting the method and the apparatus, the peak-to-average power ratio is effectively decreased, the influence of a nonlinear action of an optical-fiber channel on the signal can be alleviated, and the overall performance can be improved.

The invention belongs to the technical field of high-speed satellite communication coding modulation, and provides an unequal probability high-order constellation point design method and a demapping method. According to the method, good error performance can be obtained under the condition of nonlinear distortion caused by a high-power amplifier. The technical scheme adopted by the invention is asfollows: the unequal approximate high-order constellation point design method and the demapping method comprise the following steps: designing the occurrence probability of a two-dimensional signal constellation represented by S and each signal point on the basis of a 64-order quadrature amplitude modulation QAM square constellation diagram; completing mapping from the inequivalence symbols to the inequivalence constellation points, forming and filtering, and performing up-conversion to complete signal transmission; the receiving end firstly performing matched filtering and downsampling on the received signals, and after nonlinear demapping, directly obtaining the probability of 4-bit symbols according to a one-to-one mapping principle; and finally, sending the probability information into a multi-system code or binary code decoder for decoding. The method is mainly applied to a high-speed satellite communication coding modulation occasion.

The multi-configuration adaptive layered steered space-time coded (LSSTC) wireless transmission system utilizes Layered Steered Space-Time Codes (LSSTC), a recently proposed multiple-input multiple-output (MIMO) system that combines the benefits of the vertical Bell Labs space-time (V-BLAST) scheme, space-time block codes (STBC) and beamforming. A multi-configuration transmission scheme based on LSSTC and V-BLAST systems uses threshold-based decision making to change the modulation type and the MIMO transmission scheme in order to optimize error performance.

A cellular communication system comprises a network based radio bearer controller (123) which is arranged to control and manage the setup and operation of radio bearers. The radio bearer controller comprises a RAB processor (201) which is arranged to set up a plurality of user plane radio bearers for a user equipment (101). The plurality of user plane radio bearers all support a common service. The radio bearer controller (123) further comprises a link processor (203) which links the plurality of user plane radio bearers. The radio bearer controller (123) can process linked user plane radio bearers in relation to each other, for example by terminating all linked user plane radio bearers if a single radio bearer fails. The invention may be particularly suitable for a UMTS (Universal Mobile Telecommunication System) communication system supporting services using a plurality of UMTS user plane radio bearers.

The invention belongs to the field of smart home, and discloses a remote control system for smart home. The remote control system for smart home is equipped with a central controller, a video monitor,a home appliance wireless controller, a temperature sensor, a voice module, a light control module, a door and window control module, a power module, a short circuit protector, an LED display screenand a mobile terminal. The video monitor, the home appliance wireless controller, the temperature sensor, the voice module, the light control module, the door and window control module, the power module, the short circuit protector and the LED display screen are electrically connected with the central controller. The central controller is connected with the mobile terminal through a network. Homelife related facilities are integrated efficiently by using an integrated wiring technology, a network communication technology, an automatic control technology and an audio and video technology. An efficient residential facility and family schedule control management system is constructed. The home intelligence, safety, convenience and comfort are improved. An environment-friendly and energy-saving comprehensive intelligent home network control system is realized.

A method of decoding a low density parity check (LDPC) encoded block, with the LDPC code being defined by a parity check matrix including rows, includes processing the rows of the parity check matrix. The processing includes updating data in the rows using a split-row decoding algorithm. The updating includes partitioning each row into a plurality of partitions, and determining for each partition a first local minimum of the data of the partition. The method also includes comparing for each partition the first local minimum with a threshold, and updating at least some of the data of all partitions of the row using the local minimums or the threshold depending on the results of the comparing.

A transmit diversity apparatus of a mobile communication system includes a receiver for BLAST-decoding receiving signals from plural reception antennas to estimate channel characteristics of forward channels of each transmission antenna. The receiver then feeds back antenna-select information for selecting a transmission antenna in a good state on the basis of the estimated forward channel characteristics. A transmitter selects transmission antennas in a good state according to the feedback antenna select information, and BLAST-codes transmission symbols for the selected transmission antennas.

A system and a method are disclosed for controlling an error amplifier between control mode changes. An error amplifier comprises a first stage that comprises a first current source and a second stage that comprises a second current source and at least one compensation component that is connected to the first stage through a signal line. A buffer circuit is connected between the signal line and the at least one compensation component and a switch circuit is connected between the buffer circuit and the at least one compensation component. When switched in to the error amplifier the buffer circuit provides a value of current to the at least one compensation component that is larger than a value of current that is provided to the at least one compensation component from the signal line. This increases the slew rate of the error amplifier during a pulse frequency modulation control mode.

An error correction circuit capable of detecting burst errors included in a data signal with reliability. The error correction circuit comprises a reading unit, a first estimation unit, a second estimation unit, and a correction unit. The reading unit reads the data signal. The first estimation unit estimates error locations based on BIS code included in the data signal, and stores the locations into an error location storing unit. The second estimation unit estimates error locations based on characteristics of bit strings adjoining the BIS code, and stores the locations into the error location storing unit. The correction unit identifies erasure locations based on the error locations stored in the error location storing unit, and performs erasure correction on the erasure locations identified. Since the error locations are estimated based on the BIS code and the characteristics of the bit strings adjoining the BIS code as well, it is possible to detect burst errors without fail.

The invention discloses an object-oriented computer modeling method based on a crane boom. The object-oriented computer modeling method includes the following steps: firstly, partitioning unit modules off to acquire size, material, section and structural feature, encapsulating by an object-oriented method and creating various classes; secondly, acquiring modeling data of a crane boom structure and creating a material object, a structural steel section object and a component object; thirdly, acquiring crane-boom-type data, forming a crane boom system and storing parameters in a database; fourthly, entering the crane-boom-type data into a finite element module to create a finite element model of the crane boom system for analyzing, calculating and sending out analysis results; fifthly, extracting the data of the results according to the requirements of users and sending the data of the results, such as lists, graphs and animations to analysis report files; sixthly, finishing and releasing space. The object-oriented computer modeling method has the advantages of being strong in object-oriented modeling capacity, complete in data check function, and good in compatibility and portability.

The invention discloses an implementation method of a cooperative transmission mechanism based on feedback information. In order to enable a source and a relay in a cooperative communication system to perform better-informed information transmission operation, and to prevent unnecessary information transmitting so as not to waste resources, a target terminal feeds back 2bits information to represent three receiving states, including success, half success and failure, of signals received by a direct transmitting link at the time slot 1, and the source and the relay decide the operation at the next time slot according to the fed back information; moreover, the relay node also can select different relay transfer protocols according to whether the relay node demodulates data successfully or not. According to the invention, compared with a classic cooperative transmission mechanism, the cooperative transmission mechanism provided by the invention has the advantages that on the premise of only needing additional expenditure of 2bits, when the channel variance of the direct transmitting link is only half of that of a relay link, the spectrum efficiency also can respectively reach 120% and 133% of classical AF cooperative transmission and classical DF cooperative transmission, so that intrinsic defects of cooperative transmission are overcome, the spectrum efficiency of cooperative transmission is improved, and the error performance of cooperative transmission is also improved.

Embodiments of the invention provide a decoder for decoding a signal received through a transmission channel in a communication system, said signal comprising a vector of information symbols, wherein the decoder comprises:a processing unit (307) configured to determine at least one candidate set of division parameters and to perform a division of said vector of information symbols into a set of sub-vectors in association with each candidate set of division parameters, each pair of sub-vectors being associated with a division metric;a selection unit (309) configured to select one of said candidate sets of division parameters according to a selection criterion depending on said division metric; anda decoding unit (311) configured to determine at least one estimate of each sub-vector associated with said selected set of division parameters by applying a symbol estimation algorithm,wherein the decoder is configured to determine at least one estimate of the vector of information symbols from said at least one estimate of each sub-vector of information symbols.

A method for detecting symbols is provided in a communication system. Symbols are received simultaneously through multiple spreading code channels. The received symbols are detected by processing one received symbol at a time, calculating reliability metrics recursively from a symbol received through a first spreading code channel for each possibly transmitted symbol by comparing each possibly transmitted symbol with each rake receiver finger adapted to the received symbol at a time, and selecting, based on the reliability metrics, a number of most probable candidate symbols for further processing. The process then calculates reliability metrics from a symbol received through a second spreading code channel using the reliability metrics for the most probable candidates. The method utilizes effectively cross-correlation properties of the spreading codes associated with the spreading code channels.

The invention discloses a digital communication system based on hexadecimal three dimensional grid constellation graph mapping. The method comprises the following steps of (1) designing a QPSK constellation graph in a two-dimensional plane, and expanding and translating the QPSK constellation graph to obtain a hexadecimal three-dimensional grid constellation graph; (2) inputting a binary bit stream generated by a source into a mapping processing module; (3) inputting an obtained three-dimensional signal to a modulator; (4) transmitting a modulated signal input channel; (5) inputting a signal via the channel to the demodulator of a receiver; and (6) inputting an output signal of the demodulator into a demapping processing module for processing and enabling the processed output signal to reach a sink. The constellation graph has the regular space structure, and the error performance of the digital communication system can be effectively improved.

A memory device includes a syndrome generating circuit and a plurality of latch circuits. The syndrome generating circuit includes a plurality of input terminals and plurality of logic circuits. The latch circuits are coupled to the syndrome generating circuit and are configured to set the input terminals of the syndrome generating circuit to a predetermined logic state according to a pre-charge reset signal. The latch circuits are configured to provide a plurality of data bits to the input terminals of the syndrome generating circuit after the input terminals of the syndrome generating circuit are set to the predetermined logic state. The syndrome generating circuit is configured to generate a syndrome bit based on the data bits by the logic circuits, wherein the syndrome bit indicates a presence of an error bit among the data bits.