84 results about "Channel statistics" patented technology

Methods and apparatus for designing spherical lattice codebooks for use in data transmission systems are provided. A spherical lattice codebook is constructed by determining the channel statistics of one or more channels, which can be accomplished by observing a sufficiently large set of channel realizations. After determining the channel statistics, an expression for the error probability of the decoder or expressions for bounds on the error probability and expressions for the corresponding gradients are determined. The gradient is then used in an optimization technique to produce a spherical lattice codebook which is subsequently used for transmission.

The performance and symbol rate in a wireless mobile system are increased by forming a transmission code matrix using transformed orthogonal codes, in such a way that the code is robust to channel statistics and operates well in both Ricean and (correlated) Rayleigh channels. Furthermore, the invention enables high symbol rate transmission using multiple transmit antennas, and one or multiple receive antennas, and obtains simultaneously high diversity order and high symbol or data rate.

The performance and symbol rate in a wireless mobile system are increased by forming a transmission code matrix using transformed orthogonal codes, in such a way that the code is robust to channel statistics and operates well in both Ricean and (correlated) Rayleigh channels. Furthermore, the invention enables high symbol rate transmission using multiple transmit antennas, and one or multiple receive antennas, and obtains simultaneously high diversity order and high symbol or data rate.

Methods, systems, and devices are described for wireless communications at a wireless device. A wireless device may adaptively select a parity check matrix to increase the reliability of signal transmission by adapting to different channel statistics and channel types (e.g., erasure channels, channels with additive white Gaussian noise, and channels with discrete or continuous alphabets). For example, polarization codes (i.e., codes based on rows of a polarization matrix) may be used to construct parity check matrices “on-the-fly” given an estimation of dynamic channel conditions or diverse channel structures. The channel may be decomposed into polarized sub-channels corresponding to the polarization codes, and mutual information profiles may be determined for each of the polarized sub-channels. The parity check matrix corresponding to the polarization codes may be constructed based on the mutual information profile of all polarized sub-channels. The wireless device may encode or decode data based on the constructed parity check matrix.

A method and circuit for adaptively estimating channel conditions of a pilot channel in a wireless communication system. The method includes estimating channel statistics of the pilot channel, and adaptively filtering the pilot channel in response to the estimated channel statistics. The estimation is performed by filtering a channel signal derived from the pilot channel to determine an estimated channel mean and an estimated channel covariance. In order to perform the adaptive filtering, the present invention partitions the pilot channel into one or more time slots and weights each time slot according to the channel statistics. Thus, an advantage of the present invention is that it automatically and continually updates the pilot filter parameters in order to optimize the pilot filter performance over a broad range of channel conditions.

In an Optical Transport Network (OTN) system, methods and devices are provided for communicating rate-adaptive OTUk frames. One method determines channel statistics for a fiber span connecting a transmitter to a receiver. A client input data rate is determined that is sufficient to meet a minimum communication threshold, and a rate-adaptive OTUk frame format is determined sufficient to carry the client input data rate. The format comprises a set of (n) allocated slots of client input data in a rate-adaptive OTUk frame comprising (m) slots, where (n) is less than or equal to (m). The method then fills the rate-adaptive OTUk frame, including (m−n) unallocated slots, using one of two processes. The first process fills the rate-adaptive OTUk frame with parity bits computed from client input data. The second process fills at least a portion of the rate-adaptive OTUk frame with and dummy bits.

A communications system utilizes a forward error correction (FEC) regulation system in transmitting data to a mobile client. The FEC strength is regulated as a function of a mobile client location and channel statistics for the location. The communications system includes a server for providing the FEC, a channel statistics database for storing channel data for locations of the mobile client, and a map database. The FEC strength is based on mobile client position and channel performance statistics measured by the mobile client over a period of time and sent to the server or optionally on previously collected and stored channel statistics measurements for the mobile client position or predicted position. The collection of channel statistics is made with an automated system to create a channel statistics measurement database. The FEC strength is varied by modifying packet payload redundancy, packet time spreading, interleave characteristics and error coding rates.

A method generates signals in a transmitter of a multiple-input, multiple-output wireless communications system. The transmitter includes Nt transmit antennas. A transmit covariance matrix Rt determined using statistical state information of a channel. The transmit covariance Rt matrix is decomposed using transmit eigenvalues Λt to obtain a transmit eigenspace Ut according to Rt=UtΛtU†t, where † is a Hermitian transpose. A pilot eigenspace Up is set equal to the transmit eigenspace Ut. A Nt×Tp block of pilot symbols Xp is generated from the pilot eigenspace Up and pilot eigenvalue Λp according to Xp=UpΛp1 / 2. A data eigenspace Ud is set equal to the transmit eigenspace Ut. In addition, a Nt×Nt data covariance matrix Qd is generated according to UdΛdU†d, where Λd are data eigenvalues. A Nt×Td block of data symbols is generated, such that an average covariance of each of the columns in the block of data symbols Xd equals the data covariance matrix Qd. The block of pilot and data symbols form the signals to be transmitted.

A method and system realize reliable wireless communications in non-coherent multiple-input multiple-output (MIMO) doubly-selective channels. The method uses Grassmannian space-time-frequency block codes and an iterative generalized likelihood ratio test (GLRT) with a multi-dimensional basis expansion model (BEM), decision reordering, and a fixed number of surviving candidates. The computational complexity of a non-coherent MIMO equalizer becomes linear as a function of a code length and a size of a modulation alphabet. The codebook, the alphabet size, the bit labeling, and the block power are optimized using worst-case channel statistics or instantaneous channel states. The method can use soft-information feedback from error correction codes, such as low-density-parity-check codes to improve performance.

The invention discloses a self-adaptive switching method of transmission modes by channel statistics status information in a multi-cell cooperative downward system. The switching method comprises the steps: 1) a user confirms a cell service base station by receiving a signal to noise ratio, computes a candidate cooperative factor from the user to the other base stations in a cooperative cell cluster, and confirms the candidate cooperative base station in the cooperative cell cluster; 2) the user estimates channel information from the user to the cell service base station and from the user to the candidate cooperative base station, computes the channel statistics status information, transmits and receives a correlation matrix, and feeds the correlation matrix back to or implicitly feeds the correlation matrix back to each base station, and each base station transmits the channel status information to a central processing unit; and 3) the central processing unit computes a transmission type switching threshold according to the channel status information, and switches between the base station cooperative transmission mode and the base station non-cooperative transmission mode by comparing the receiving signal to noise ratios with the transmission type switching thresholds between the user and the cell service base station.

An adaptive coding scheme for nonlinear channels improves reliability and an efficiency in digital communication networks. The method monitors channel statistics to analyze an extrinsic information transfer chart of the channels. The channel statistics are fed back to the transmitter to adapt forward error correction coding. A parametric analysis method uses a Gaussian mixture model. The statistical information feedback can adapt an ARQ sheme by adding a weighted received signal to the original coded signals to reduce nonlinear distortion. Trellis shaping, can make the transmitting signal preferable for nonlinear channels.

A distributed and opportunistic medium access control (MAC) layer protocol for randomized distributed space-time coding (R-DSTC), which may be deployed in an IEEE 802.11 wireless local area network (WLAN), is described. Unlike other cooperative MAC designs, there is no need to predetermine, before packet transmission, which stations will serve as relays. Instead, the MAC layer protocol opportunistically recruits relay stations on the fly. Network capacity and delay performance is much better than legacy IEEE 802.11g network, and even cooperative forwarding using one relay station. Avoiding the need to collect the station-to-station channel statistics considerably reduces overhead otherwise required for channel measurement and signaling.

The present invention relates to a speech recognition error correction method and device. The method includes the following steps that: historical recognition results obtained by a current speech recognition model are acquired, wherein the historical recognition results include a plurality of pieces of text information; logical analysis is performed on the plurality of pieces of text information, and target text information with repeat logic is extracted; the target text information with repeat logic is subjected to wrong channel statistics, so that a text alignment model can be generated; speech information inputted by a user is received; and the speech information is decoded according to the current speech recognition model and the text alignment model, so that a target speech recognition result is obtained. With the speech recognition error correction method and device provided by the technical schemes of the invention adopted, the obtained speech recognition result can be more accurate and better meet the requirements of the user, and therefore, the use experience of the user can be enhanced.

The invention relates to a method for assigning integrated routing and channels of cognitive wireless mesh networks. The method comprises the following steps that: a, a node senses external environment, broadcasts sense information to neighboring nodes, and acquires a list of the neighboring nodes; b, the node attempts to pass a topological form of a routing tree and chooses assignment channels according to metric values of channel statistics; c, the nodes are connected to a network, and by sorting hop counts and the metric values of channel statistics, the node with few hop counts or a small metric value of channel statistics is chosen as a father node; and d, the nodes exit from the network, and an exiting mode is chosen on the basis whether the node is the father node or a child node, and the information of the routing tree is updated. The method has the advantages of considering the characteristics of the dynamic change of the number of spectrum holes in cognitive environment, reasonably and effectively assigning channels and selected routing, balancing channel load, reducing interference between adjacent channels, avoiding too heavy load of individual channels and increase in time delay, giving full play to the advantages of multi-channel parallel transmission and improving network transmission performance.

A system and method for wireless communications using spatial multiplexing with incomplete channel information is provided. A method for wireless communications includes receiving a reference signal from a communications device, computing at least one first beamforming vector from the received reference signal, selecting at least one second beamforming vector from channel statistics, and transmitting information to the communications device. The reference signal is transmitted using a subset of antennas used for data reception at the communications device, and the transmitting uses the at least one first beamforming vector and the at least one second beamforming vector.

The present invention provides an optimal power distribution and relay deployment method of a full duplex bidirectional decoding forwarding relay based on a channel statistics characteristic. The method comprises the following steps of establishing a bidirectional full duplex relay communication system; using a terminal node to send the state information to a relay node, wherein the state information comprises the emission power information and the self-interference information; after the relay node receives the state information of the terminal node, selecting an optimal power distribution scheme to send a signal; and selecting the deployment position of the relay node according to an optimal power optimization scheme. According to the present invention, and according to a deployment mechanism of the relay node, a power distribution mechanism of the relay node enables the interruption probability of a system to be reduced effectively, the problem that the interruption probability is overhigh in a full duplex system is solved, and the stability of the system is improved, thereby improving the service quality of the terminal node.

A statistical method for the multiple transport flow includes initialization, statistics of input information and multiple transport streams etc. The invention provides a simple and efficient method completely without encoder, which is used for the multi-channel statistics of basic document flow of video and audio.

A method and apparatus are provided for a wireless communication system including a base station and at least one user equipment. A Channel Quality Indicator (CQI) table can be generated so that only an index corresponding to the measured CQI needs to be fed back to the base station. The CQI tables proposed herein may be suitable to different channel statistics, different Multiple Input Multiple Output (MIMO) mode and may be optimized based on either performance or implementation complexity. Multiple CQI tables may be formed into one compound CQI table. The CQI tables may be stored at both a base station and user equipment. The base station can select a CQI table from the set of tables. The base station signals the selection of the CQI table to the user equipment and the user equipment feeds back indices from the selected CQI table to the base station.

The embodiment of the invention provides a download channel statistics processing method and device for application programs and an electronic device. The method on the electronic device side comprises the following steps: receiving an operation instruction input by a user on a page corresponding to a first channel; transmitting first parameter information of the electronic device to a server according to the operation instruction, the first parameter information being used to identify information of the electronic device, and information of the first channel and time information during inputof the operation instruction by the user; determining whether the application program is started for the first time; if so, sending second parameter information of the electronic device to the server,wherein the second parameter information is used to identify the electronic device information and the first start-up time information of the application program. The method realizes the statistics of download data of download channels.

A system and method that may facilitate transmission bandwidth savings in non-stationary vehicle-to-vehicle wireless communication channels. At a transmitting vehicle, a transmitter may adaptively change the number of pilot symbols or pilot rate within a frame based upon the current channel statistics. The transmitter may utilize a look-up table approach to select a best pilot rate based upon current conditions associated with the transmitting vehicle, and / or a new frame structure to transmit pilot rate information. At the receiving vehicle, the receiver may be configured to detect a unique waveform transmitted by the transmitting vehicle to estimate the pilot rate information. Alternatively, the receiver on the receiving vehicle may be configured to predict and verify the pilot rate information from an encoded data symbol embedded within a frame transmitted by the transmitting vehicle, which may entail a detection algorithm using encoded data symbols and / or an estimation algorithm using channel statistics.

The invention provides a mobile satellite uplink adaptive coding and modulation method based on partial channel information. For realizing adaptive coding and modulation of ground terminals, a transmitter obtains equivalent uplink line of sight channel information through an open loop method according to reciprocity of mobile satellite uplink and downlink line of sight channel information, and bya closed-loop system, the transmitter obtains multi-path channel statistics information fed back by a receiving end. The invention also provides an optimal adaptive algorithm suitable for the mobile satellite uplink, wherein a ground end calculates an optimal switching threshold through an optimization algorithm based on the acquired partial channel information, and thus, adaptive switching of coding and modulation modes is realized. The method provided by the invention effectively overcomes boundedness of the existing mobile satellite adaptive method, avoids influence of channel information feedback delay on adaptive performance and guarantees implementation of reliable and efficient adaptive coding and modulation under a mobile satellite communication environment.

The invention discloses a real-time constructor safety helmet detection method based on pedestrian detection. According to the method, firstly, large-scale marked samples are utilized to carry out multi-time iteration training for an Adaboost classifier extracted on the basis of ACF characteristics; secondly, the trained classifier is utilized to carry out pedestrian detection on a video sequence, and the precise position and the quantity of targets are determined; thirdly, locus analysis on a detection result is carried out, whether the detection result is wrong is determined according to the locus information, if a score of the detection result is not high, dump processing is carried out, the detection result with high score is tracked, a characteristic that a human head is at a top portion of the detection result is utilized, the portion of a safety helmet is locked, through color space conversion, and safety helmet detection is finally realized through utilizing a pixel ratio for determination according to the separation color channel statistics pixel information. The method is advantaged in that good robustness is realized for multiple occasions, and a pixel point statistics detection method based on HSV space has quite good effects for special color safety helmets.

The invention discloses a rateless-code degree number distribution optimization method of cloud access network uplinks. The method is for a single-user uplink transmission system under block fading channels, a user uses rateless codes to encode original information, and sends information to remote radio heads (RRHs) after modulation, and the remote radio heads quantize received signals, and send quantized results to a baseband processing unit pool through high-speed forward-transmission links. The invention provides the single-user rateless-code transmission degree number optimization method for a case where only channel statistics information is known, and the problem of needing global real-time network information state information in traditional methods is avoided. The designed method of degree number distribution of the invention can improve system throughput.