283results about How to "Improve bit error rate" patented technology

The invention provides a neural network equalization method used for an indoor visible light communication system, and belongs to the visible light wireless communication technology field. The method includes the steps: utilizing a ceiling bounce model to calculate a VLC channel impulse response, carrying out photoelectric conversion for a visible light power signal received by a receiving end, and sending a sequence to a neutral network channel equalizer after amplification sampling; utilizing a heredity algorithm to optimize initialization weights and thresholds among neurons, establishing a neural network for training, and minimizing an error function; and judging an output, restoring the sent sequence, and finally achieving an equalization purpose. According to the scheme, interference among codes is obvious minimized, an error rate is reduced, the communication quality is further improved, a transmission rate that the system can reach is increased, the training time is shortened, and the system complexity is reduced.

The present invention discloses a data transmission method of the multimedia broadcasting multi-broadcasting service (MBMS), predefining the punching information of a MBMS data subframe. The method includes two steps. Firstly, an evolutionary universal terrestrial radio access network base station (eNB) punches the present MBMS data subframe according to the defined punching information, maps the control signals of the downlink physical layer on the punched position and maps the MBMS data on the unpunched position, and then the MBMS data subframe is sent to the user equipment (UE); secondly, according to the punching information corresponding to the present MBMS data subframe, the user equipment (UE) acquires the control signals of the downlink physical layer from the received present MBMS data subframe, and according to the requirement, acquires the MBMS data. The present invention also provides a network device sending the MBMS data subframe and a terminal device receiving the MBMS data subframe. The present invention can increase the throughput rate of a communication system and enhance the flexibility of dispatching.

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.

The invention discloses a method of modulating a variable pulse amplitude position and improving an error rate for a visible light communication system, belonging to the field of visible light wireless communication technologies. According to the method, modulation of the variable pulse amplitude position is utilized in a modulation module of a signal transmitting end, a modulation method is multi-system modulation capable of combining pulse amplitude position modulation and pulse width modulation, transmission of communication data is guaranteed while a system dimming function is provided, improvement of the communication quality mainly includes that the transmission rate can be improved under the condition of the same symbol rates, the advantages of high multi-system modulation bandwidth efficiency and high pulse position modulation power efficiency are combined, the spectral efficiency can be effectively improved, and compared with the other multi-system modulation manner, the complexity is lower. In order to further improve the error rate of the visible light communication system, the method utilizes a channel balancer based on a feed-forward back propagation multilayer perceptron on a receiving end, so that the error rate is effectively improved, and the communication quality is further improved.

A high speed data link includes transmitter equalization and (passive) receiver equalization to compensate for frequency distortion of the data link. In one embodiment, the transmitter equalization is performed with a de-emphasis circuit. The transmitter de-emphasis circuit pre-distorts an input signal to compensate for at least some of the frequency distortion in the data caused by the transmission line. The (passive) receive equalization circuit further compensates for the frequency distortion at the output of the transmission line to flatten the amplitude response of the output signal, and thereby reduce inter-symbol interference, improve media reach and improve the bit error rate (BER).

The invention relates to a multifunctional integration embedded static image compression system, wherein the image gathering module comprises a video decoder, a video gathering programmable logic device and the corresponding static storage, the image compression module comprises a digital signal processor for preliminary treatment, small wave conversion, entropy encoding, rate control and packing with the corresponding synchronous dynamic memory, and the data transmission module comprises a main controller and a general purpose serial controller. The invention realizes visualized control for rate flow with the transmission velocity of flow compression as high as 480Mbps.

A method performs a hybrid automatic repeat-request (HARQ) operation in a wireless orthogonal frequency division multiple access (OFDMA) network. A quality of a channel between a transmitter and a receiver is estimated as an error metric. A packet for the HARQ operation is fragmented adaptively at the transmitter according to the estimated error metric. The fragmentation is performed at the HARQ layer when the error metric is less than a predetermined threshold, otherwise the fragmentation is performed at the MAC layer.

The invention discloses a timing frequency synchronization method based on an improved Park frequency domain training sequence. The timing frequency synchronization method comprises the following steps: firstly sending a training sequence before an OFDM data symbol is sent, wherein all the sub carriers of the training sequence in the frequency domain respectively send a pseudorandom real number, and structure of a corresponding time domain training symbol is conjugate symmetric; performing timing synchronization by an FS-Park synchronization method firstly by using the time domain training symbol, then performing estimation on fractional part of frequency offset based on a cyclic prefix in the time domain and performing estimation on integral frequency offset by utilizing cross correlationof the training sequence in the frequency domain, obtaining the total frequency offset, namely the sum of the integral frequency offset and the fractional part of frequency offset, and completing synchronization. The timing frequency synchronization method disclosed by the invention designs a new training sequence, and then a more ideal time domain training symbol structure is obtained; and thenbased on the training sequence and the corresponding time domain training symbol thereof, the integral frequency offset and the fractional part of frequency offset are estimated respectively, and timing synchronization estimation is performed.

The invention involves a parallel spread spectrum ('PSS') technique of spreading orthogonal encoded data. In a preferred embodiment, a method and system for communicating data comprises encoding and spreading a data stream using a scheme employing orthogonal Walsh functions, and thereby segmenting the data stream into multiple bit data packets representing one of a number of true or inverted Walsh codes. The data stream is then differentially encoded for either BPSK or QPSK modulation, and spread using a PN-sequence. The parallel spread data stream is modulated for transmission to a receiver. At the receiver, the data stream is recovered by computing a cross correlation between the digitized data stream and a programmed sequence. One of the benefits of the PSS techniques over conventional communication systems is that additional processing gain plus data forward error correction can be simultaneously achieved.

The invention provides a free space optical communication method and system based on an LDPC code. The method and system aim at a problem that the error rate, communication distance and communication bandwidth of a system are affected by the flicker and light beam drift and extension caused by atmosphere turbulence and the reduction of signal to noise ratio of a receiving end in laser communication. The method comprises the steps: firstly proposing a logarithmic normal distribution channel model under weak turbulence and a K-distribution channel model under strong turbulence according to the characteristics of atmosphere turbulence channels; secondly constructing an irregular QC-LDPC code on the basis of the proposed channel models; finally deducing an LLR probability density function, and carrying out the decoding through an LLR-BP algorithm. A confidence decoding BP result indicates the error rate of the system remarkably decreases along with the increase of signal to noise ratio. An experiment indicates that the method and system can effectively reduce the performance of an FSO system.

The invention discloses a user interface protocol stack, applied to radio evoluted networkin two-layer node structure, comprising IP access gateway (IAGW) user interface protocol stack, edge radio station (ERS) user interface protocol stack and uer end (UE) user interface protocol stack, where the IAGW user interface protocol stack comprises: layer L1, layer L2, IP layer and higher layer; the ERS user interface protocol stack comprises equivalent layer L1, layer L2, IP layer and higher layer on E-I interface side between it and IAGW; the radio interface side comprises: radio layer L1, lower layer and head compression layer; the UE user interface protocol stack comprises equivalent radio layer L1, lower layer and head compression layer to those on ERS radio interface side. And the invention also discloses a head compressing method in the two-layer node structure, implementing head compression of air interface data packet between ERS and UE.

A method and apparatus for mapping a stream of bits output from an encoder to a stream of bits for 2^m-ary modulation. The method and apparatus divides the stream of bits from the encoder into a first period and a second period. The first period includes bits with higher priority in the stream of the bits output from the encoder, and the second period includes bits with lower priority. The method and apparatus maps the bits existing in the first period to bit positions with higher reliability in a stream of m bits representing each of the bits for 2^m-ary modulation, and maps the bits existing in the second period to bit positions with lower reliability in the stream of m bits.

The invention discloses a method and a system for efficiently restraining large PAPR of OFDM system based on companding, wherein the PAPR is debased and the error rate is reduced. The invention is characterized in that the invention provides a companding method for reducing the probability of generating large PAPR based on hyperbolic asymptote companding function by analyzing the fundamental reasons to the PAPR problem in the OFDM system and the factors of generating low probability of large PAPR, starting compressing time-domain large signal, enlarging time-domain dwarf signal and limiting super-large signal in combination with the advantages of amplitude limiting and companding. The invention is applied to OFDM system.

The invention discloses a precoded multiple-input-multiple-output-optical-frequency-division-multiplexing (MIMO-OOFDM) visible light communication method. The method comprises: channel matrixes of all users in an indoor environment are obtained; according to the indoor environment channel matrixes, a precoded matrix of each user is calculated by using a BD method; a bit data flow of each user is modulated by an spatial modulation (SM) or spatial pulse position modulation (SPPM) device to obtain a data vector of the user; according to a precoded matrix Pj, data of a user j after precoding are obtained; the data after precoding are modulated by using OOFDM to generate a to-be-transmitted optical signal of each LED lamp; OOFDM demodulation recovery is carried out on a received optical signal at a receiving end of each user; signals after the OOFDM demodulation are recovered; and then demodulation is carried out to obtain a bit data flow of each user.

An embodiment of the invention provides a method and a device for generating an optical signal based on geometric-probability shaping. The method comprises the following steps: acquiring original datato be sent; determining, according to sequence numbers of each constellation subset, a subset serial number sequence obeying the optimal distribution corresponding to the original data, and determining a binary sequence of the subset serial number sequence obeying the optimal distribution corresponding to the original data according to binary labels of each of the constellation subsets, wherein the constellation subsets are obtained by performing subset division on the multi-mode circular constellation after performing geometric forming on square constellation diagrams of the preset number ofconstellation points to obtain a multi-mode circular constellation; systematically coding the binary sequence to obtain the encoded information; sequentially selecting a first preset number of information bits and a second preset number of redundant bits for the encoded information, and mapping the above bits to the multi-mode circular constellation to obtain an optical signal to be transmitted.This embodiment enables the transmitted light signal to approximate the Shannon channel capacity.

The invention discloses a wireless energy and data synchronous transmission system and a parameter acquisition method thereof, and belongs to the technical field of wireless electric energy transmission, and solves the problems that the volume is large and the error rate is increased along with the increase of transmission power existing in an existing wireless energy and data synchronous transmission scheme. A data signal to be transmitted serves as a modulating signal, and a high-frequency alternating-current voltage signal serves as a carrier signal. The modulating signal is adopted for modulating the carrier signal so as to obtain a modulated signal carried with data. The modulated signal is superposed onto an energy signal to be transmitted so as to obtain a superposed signal. The superposed signal is wirelessly transmitted to a secondary side circuit from a primary side circuit through a loose coupling transformer. The superposed signal transmitted to the secondary side circuit is separated into a modulated signal and an energy signal. The separated modulated signal is demodulated into a data signal. The system is applicable for wireless synchronous transmission of energy and data.

The invention presents a color and intensity shift keying (CISK) modulation method for a visible light communication (VLC) system. The basic principle is to combine a non-zero-level pulse amplitude modulation (NZL-PAM) technology and a color-shift keying (CSK) modulation technology and add a CSK signal to a variable-intensity optical signal. Through the combination, the two-dimensional constellation diagram of original CSK is extended to a three-dimensional space, and the degree of freedom of spatial distribution of symbols is increased. Meanwhile, through reasonable design of the level of NZL-PAM, the minimum Euclidean distance of the constellation diagram can be increased, and the symbol error rate of the system can be enhanced.

The invention relates to methods for transmitting and receiving a data bit stream in a communication system using a 16-QAM constellation. Further, an apparatus for performing the methods is provided. To provide a modulation and coding scheme using a signal space expansion and 16-QAM which improves the bit-error rate in comparison to QPSK modulated signals and still provides the possibility to implement coders and decoders with low complexity the invention suggests the use a 16-QAM constellation with specially selected mapping rules together with repetition coding (signal space expansion) and interleaving of the data stream to be transmitted.

The invention provides a music playing score matching method, a storage medium and a smart musical instrument. The method comprises: playing information in a preset time period is collected, wherein the playing information includes playing sequences and playing time of keys or strings during electronic music device playing by a user; the playing information in the preset time period is identifiedand a playing score in the preset time period is obtained, wherein the playing score includes sound levels corresponding to electronic music device playing, sound level time, and a sound level sequence; and the playing score is compared with a pre-stored standard score and the standard score having a matching degree with the playing score reaching a preset value is extracted. Therefore, problems that the environmental factor interference is high, the bit error rate is high, and the sample accuracy requirement is high according to the existing music information matching technology and problemsthat the user needs to carry out operation to realize semi-automatic page turning of the music score, the score needs to be replaced manually, and the user experience is poor according to the existingmusic score following device can be solved.

The invention discloses an optical fiber nonlinear equalization method based on KNN algorithm without data auxiliary. The method comprises the following steps: acquiring a distribution density parameter of each data point, performing signal modulation by selecting the data point with the distribution density parameter greater than the preset threshold, acquiring labels corresponding to various data points, dividing into M clusters according to the labels so as to acquire the corresponding centroids; reclassifying the data points according to Euclidean distance according to the acquired centroids to construct a training sample set; taking the data point X not acquiring the label, acquiring K closest neighbor point of the data point X from the training sample set; computing the KNN Euclideandistance of the data point X, and finding the label cluster of K closest neighbor points; determining a prediction label of the data point X by using a weighted sum voting rule, and distributing theX to the corresponding cluster; repeating the above steps until accomplishing the processing on all data points. Through the optical fiber nonlinear equalization method disclosed by the invention, thecomputation complexity is greatly reduced, the zero redundancy of the system is realized, the classification performance of the system can be obviously improved, and the system error rate is improved.

The invention discloses a method for reducing the PAPR of an OFDM system through an improved SLM algorithm and relates to an OFDM technology. The method for reducing the PAPR of the OFDM system through the improved SLM algorithm aims to solve the problem that the system error rate of an existing non-sideband transmission SLM algorithm is high, and includes the first step of determining a frequency domain data vector of an OFDM signal, the second step of processing the input vector X through the improved SLM algorithm, the third step of carrying out IFFT on obtained D paths of independent output vectors S(d) to obtain D paths of time-domain signals, the fourth step of selecting and sending the path of signal with the minimum PAPR value, the fifth step of carrying out FFT on the received D paths of signals by a receiving end, the sixth step of carrying out module picking on the obtained D paths of signals after FFT, the seventh step of estimating out which path of signal is emitted by an emitting end and the eighth step of recovering original signal information. The method is applied to the field of wireless communications.

The invention relates to a video coding device and method applicable to a low-bandwidth wireless communication channel. The device comprises a transmitting terminal module and a receiving terminal module; the transmitting terminal module comprises fiver submodules, including a video collection submodule, a video compression submodule, a first I frame data judgment submodule, an RS (reed-solomon) coding submodule as well as a network transmitting submodule; the receiving terminal module comprises five submodules including a network receiving submodule, a second I frame data judgment submodule, an RS decoding submodule, a video recovery submodule and a video display submodule; when the first I frame data judgment submodule judges that the current compression code stream is I frame data, the RS coding submodule performs forward error correction coding for an I frame in the compression code stream before transmitting, so as to recover the complete I frame; and when the second I frame data judgment submodule judges that the current compression frame data is I frame data, and when the RS decoding submodule decodes an IDR image, a reference frame queue is cleared immediately, all decoded data is output or abandoned, a parameter set is found again, and a new sequence is started up. The invention also relates to a coding method of the device.

The invention discloses an improved SVM equalization method and system for an NG-PON. The method in the invention comprises the steps of: (1), inserting training sequences into digital signals needingto be transmitted every the set length, generating electrical NRZ signals through high-rate NRZ modulation, and converting the high-rate electrical NRZ signals including the training sequences into optical NRZ signals; (2), transmitting the optical NRZ signals to a receiving end, and converting the received optical NRZ signals into the electrical NRZ signals; (3), performing up-sampling on the electrical NRZ signals, and performing down-sampling after time synchronization; (4), extracting the training sequences, constructing a characteristic value vector for each training sequence, and calculating an optimal hyperplane; (5), judging information sequences by utilizing the optimal hyperplane, so that equalization is realized; and (6), returning to the step (4) after equalization of the information sequences is completed every the set length. According to the improved SVM equalization method and system for the NG-PON disclosed by the invention, the problem that the receiving sensitivityof the system is decreased due to signal distortion, intersymbol interference and the like introduced by bandwidth limitation when high-rate signals are transmitted by a low-bandwidth device can be solved.

A processor (110) is disclosed for processing a plurality of Fourier-transformed instances of a symbol, each instance being comprised in one of a plurality of frequency-divided multiplexed subcarriers, said processor being arranged to estimate, for each instance, the channel gain and the inter-carrier interference contribution to said symbol from neighboring subcarriers due to a time-varying channel response of the received signal, and combine the instances into a single representation of said symbol based on the estimated channel gain and the inter-carrier interference contributions. A receiver comprising such a processor and a method for processing such signals are also disclosed.

The invention relates to a fully-integrated photoelectric conversion receiver based on standard CMOS process. The fully-integrated photoelectric conversion receiver comprises a photoelectric detector, a trans-conductance amplifier, an equalizer, a multi-stage limiter, a DCOC (decentralized classic optimal control) processing circuit, an output buffer, a slope detector and an error amplifier, wherein the P end of the photoelectric detector is grounded, and the N end is connected with the input end of the trans-conductance amplifier; the trans-conductance amplifier is connected with the differential input end of the equalizer through a high-pass circuit; the output end of the equalizer is connected with the differential input end of the output buffer through the multi-stage limiter; and the differential input end of the input buffer is connected with the output end of the equalizer through the DCOC processing circuit. The fully-integrated photoelectric conversion receiver provided by the invention is adaptive to transmission with higher data rate, can suppress jitter and error rate, can realize self-adaptive regulation, and can be widely used in the field of communication technology.