45 results about "Planisphere" patented technology

The general demodulation (DEMOD) method includes steps: under precondition of accorded with sample theorem, full phases FFT, and required corrected sampling points to select A/D conversion for the sampling frequency (FR); selecting sequence needed by full phases from the sampling sequences, and then based on FR spectrum correction (FSC) technique to select the correction sequence; carrying out FFT in full phases for the selected sequence, and meanwhile based on the selected FSC technique to carry out FSC so as to accomplish demodulation (MOD); using planisphere-mapping to accomplish decoding. Since DEMOD is based on full phases FFT, the algorithm for correcting and accurate estimating FR, phase, and amplitude is simple so as to simplify DEMOD circuit. Features are high resolution for estimating FR and phase, and low error rate. The invention is suitable to multiple MOD modes including different distributions of planisphere so as to be in favor of generalization of demodulator.

The invention discloses a wireless optical orthogonal multi-carrier communication method with a low peak to average power ratio. The wireless optical orthogonal multi-carrier communication method comprises the following steps that at a transmitting end, firstly, modulated frequency domain signals are converted into a semi-positive definite planning convex optimization problem by adopting a tone injection algorithm via a relaxation method, and solving is carried out through general convex optimization and randomized methods; secondly, the frequency domain signals are symmetrically mapped to subcarriers in a conjugate mode, and a cyclic prefix is added after reverse fast Fourier transformation; at last, time domain transmission signals are added into direct-current offset to drive a light-emitting diode to emit light. At a receiving end, photovoltaic conversion is achieved through a photodiode; signals are removed from the cyclic prefix and conjugate symmetry parts after amplification, filtering, analog-digital conversion and fast Fourier transformation; the signals are modulated to be recovered in an original planisphere; at last, receiving symbols are obtained through demodulation. According to the wireless optical orthogonal multi-carrier communication method, the peak to average power ratio of a wireless optical communication PFDM system can be effectively reduced, requirements of a power amplifier and an LED for linear degrees are reduced, non-linear distortion is reduced, and receiving performance is improved.

The invention belongs to the field of optical communication, and is applied to the polarization demultiplexing of a polarization diversity multiplexing coherent optical communication system. According to the invention, for the problem of the polarization demultiplexing in the polarization diversity multiplexing coherent optical communication system, a special training sequence and related algorithms are designed. Through the method, a coherent receiver can fast, automatically and accurately perform the polarization demultiplexing. As the track of the training sequence, viewed from a planisphere, rotates along a unit circle after sign power is normalized, the training sequence provided by the invention is called a constant rotation sign training sequence. The invention discloses two processing algorithms for the constant rotation sign training sequence, which are a frequency-domain algorithm and a time-domain algorithm respectively, wherein the frequency-domain algorithm can be combined with frequency-domain dispersion compensation without adding a frequency spectrum calculation module. Through the method, the receiver does not need synchronizing with an initial position of the training sequence.

The invention discloses a constellation mapping de-mapping and the linear transformation planisphere mapping de-mapping method and the device, wherein the planisphere mapping method includes: performing the planisphere mapping to the coded and interweaved stream of bits according to planisphere satisfying G(alpha*d+ beta*D) smaller than the given threshold, mapping the code word onto the corresponding constellation point, transmitting the output signal flow after the post-treatment, wherein G is the cost function, d is the statistical value of the smallest euclidean distance of the input code word set, D is the statistical value of the smallest Hamming distance of the input code word set, alpha and beta are the weight coefficients which are selected according to the characteristics of the practical channel. The invention causes the modulation demodulation system to obtain the compromise between the receptivity of the gaussian channel and the fading channel, namely causes the modulation demodulation system to have the satisfying receptivity below the gaussian channel and the fading channel and other channels therebetween.

The invention discloses a 12-point SCMA codebook design method based on a hexagonal planisphere and a SCMA system using the method. The codebook design method comprises the following steps: 1, allocating 12 constellation points on the end points of two embedded hexagons to form a total planisphere on a resource block; 2, splitting the total planisphere into 3 sub planispheres according to the principle that the minimum Euclidean distance on the same planisphere is the maximum, and separately expressing the 3 sub planispheres as S1, S2 and S3, wherein the size of each sub planisphere is 4; 3, generating a codebook of each user according to an incidence matrix F of the SCMA system and the sub planispheres used by different users on different resource blocks; and 4, performing power normalization on the codebook of each user so as to generate a system codebook. The codebook designed by the method has the advantages of low complexity, low error rate under high signal to noise ratio and convenient hardware implementation.

The method includes steps: (1) rotating the received signal and relevant coordinate of planisphere 45 degree in clockwise; (2) calculating b0' possible log likelihood ratio of b0, b0' takes maximum of calculated values; if b0' is larger than 0, then b0 = 0; otherwise b0 = 1; (3) rotating the received signal and relevant coordinate of planisphere 45 degree in anticlockwise, and calculating b1 according to the method; based on results of b0 and b1, adjusting the signals above; (4) calculating b2' and b3' according to b2' = x+y, b3' = y - x; if calculated result is larger than 0, then demodulated result of corresponding bit is 0, otherwise, demodulated result is 1. Features are simple, less amount of calculation, ensuring demodulation performance effectively so as to raise demodulating efficiency and quality of 16 QAM in TD - SCDMA system.

The embodiment of the invention discloses a carrier adaptive filtering method and a system of zero intermediate frequency, and a corresponding zero intermediate frequency receiver. The method comprises the following steps: de-spreading an I signal filtered by a first FIR filter and a Q signal filtered by a second FIR filter; calculating the errors of the de-spread I signal and Q signal between the coordinates in the planisphere and the ideal coordinates in the planisphere by using an EVM method; and adjusting the coefficients of the first FIR filter and the second FIR filter according to the errors, until both the differences between the coefficients of the first FIR filter and second FIR filter before and after the adjustment are less than the preset threshold. The invention can effectively inhibit zero-frequency components and I/Q mismatch, does not need to interrupt the effective signal, and can be used in a WCDMA downgoing signal or CDMA downgoing signal receiver system.

The invention relates to a method for establishing a communication system three-dimensional planisphere. The method comprises the steps that a modulation point number M of the target three-dimensional planisphere is determined; through planimetry operation, all two-dimensional hexagonal cell planispheres with modulation point numbers smaller than or equal to M are listed, and the minimum Euclidean distance of the two-dimensional hexagonal cell planispheres is 1; through solid geometry operation, the obtained two-dimensional hexagonal cell planispheres are combined, so that a plurality of candidate three-dimensional planispheres with the total modulation point number equal to M are obtained; the total energy of the candidate three-dimensional planispheres which meet the requirement that the minimum Euclidean distance is 1 is computed; and a candidate three-dimensional planisphere with the minimum total energy is selected as the target three-dimensional planisphere. According to the method, the designing complexity of the three-dimensional planisphere can be greatly lowered, and the three-dimensional planisphere with small average energy and good bit-error-rate performance can be obtained.

The invention discloses a signal-to-noise-ratio estimation method and device based on hard decisions and also discloses a method and device used for signal-to-noise-ratio estimation. Each hard-decision area on a planisphere is divided into two subareas which are different in hard-decision reliability in advance and a weighting factor corresponding to each subarea is set. When reception signals are available, a subarea which the reception signals belong to is determined and estimated transmission-signal power is corrected by using the weighting factor corresponding to the subarea and then the corrected power is used to estimate a signal-to-noise ratio so that errors in signal-to-noise-ratio estimation are reduced.

The method includes steps: based on data information after channel equalization to carry out QAM mapping so as to obtain ideal position QAM_out of data information on planisphere; calculating first function value YH_QAM and second function value HH of the point on planisphere corresponding to the data information; first function includes factors of channel information, ideal position QAM_out, and data information before channel equalization; second function includes factor of channel information; first function and second function constitute distance of deviation Dist of the point related to the ideal position; accumulating first functions and second functions of corresponding points; using the accumulated first function value and second function value to calculate SNR.

The invention provides a detecting algorithm based on planisphere reduction in a high order modulation MIMO system. The problem that a detecting algorithm in the high order modulation MIMO system is high in complexity is solved. According to the detecting algorithm, a planisphere is reduced, tree expansion is performed according to the reduced planisphere, and the planisphere reduction scheme can be selected in a self-adaptive mode according to the state of a channel. The advantages of the detecting algorithm in an actual value model are fully used. The simulation results show that the self-adaptive detecting algorithm based on planisphere reduction is low in BER, greatly reduces the complexity of the detecting algorithm and has the advantages in the aspects of the BER and complexity. Compromise between the BER and the complexity of the algorithm can be achieved by adjusting parameters, and the detecting algorithm is suitable for the high order modulation MIMO system.

A timepiece for displaying a planisphere and indicating a portion of the planisphere. Another exemplary embodiment is a clock that displays both sidereal and solar time, while indicating a portion of the planisphere at a particular time. Another exemplary embodiment of the timepiece includes an adjustment feature that allows a user to adjust the portion of the planisphere indicated to a particular geographic location. An exemplary embodiment may contain a celestial or terrestrial planisphere. As a result, an exemplary embodiment of the timepiece may provide valuable information about the planisphere at any particular sidereal or solar time.

The invention relates to the technical field of communication, in particular to a method, equipment and a system of indicating and confirming a transmission format combination. The method, the equipment and the system of indicating and confirming the transmission format combination are used for solving the problems that in the prior art, system overhead is increased and network transmission efficiency is reduced by adopting an explicit type indicating transmission format combination. The method of indicating the transmission format combination comprises the steps that a sending side confirms a planisphere mapping mode combination corresponding to a transmission format combination of a receiving side needing indications according to a corresponding relation of the transmission format combination and the planisphere mapping mode combination, and confirms modulation symbols corresponding to each set of transmission data, and sends the confirmed modulation symbols to the receiving side according to corresponding planisphere mapping modes corresponding to each set of transmission data of the confirmed planisphere mapping mode combination. By using the corresponding relation of the transmission format combination and the planisphere mapping mode combination, and an implicit type indicating transmission format combination, the method, the equipment and the system of indicating and confirming the transmission format combination avoid the system overhead needed by the explicit type indicating transmission format combination, and improve network transmission efficiency.

The invention provides a hierarchical modulation type 32APSK planisphere design method, which can be applicable to 32-order APSK hierarchical modulation systems. The method comprises the following steps: step 1, constellation point arrangement: allocating 32 constellation points in three concentric circles with different radiuses in a two-dimensional plane, wherein 4 constellation points are allocated in the first circle, and 1 constellation point is allocated in each quadrant, 12 constellation points are allocated in the second circle and 3 constellation points are allocated in each quadrant,16 constellation points are allocated in the third circle and 4 constellation points are allocated in each quadrant, the constellation points in the same circle are not uniformly distributed in a 360-degree plane, and the coordinate axes of different quadrants are symmetrical; step 2, on the basis of the arrangement of the constellation points in step 1, determining the positions of the constellation points in the plane; and step 3, on the basis of the planisphere obtained in step 2, determining mapping codes of the constellation points in the modulation to obtain an optimal mapping code set,namely a complete planisphere.

The invention relates to a method for recognizing subcarrier modulation modes of an orthogonal frequency division multiplexing signal in wireless communication, belonging to the field of wireless communication signal processing. The method comprises the following steps of: firstly; preprocessing a received radio-frequency signal by a receiving end of a wireless communication system; extracting N symbols from the received orthogonal frequency division multiplexing signal; respectively carrying out complementation, blind channel estimation and balance on the N symbols to acquire a modulation signal on a data subcarrier so that the modulation signal is matched with the planispheres of all the subcarrier modulation modes of the orthogonal frequency division multiplexing signal; and selecting the modulation mode with the maximum matching degree as a recognition result. An OFDM (Frequency Division Multiplexing) robust blind channel estimation algorithm when a virtual subcarrier exists is adopted in the method of the invention, which is suitable for a time-varying multi-path environment for balancing a non-ideal channel and has the advantages of simple flows, little amount of calculation, short observation time and time-varying channel environment suitability.

The invention discloses a hard decision method using a single antenna to solve double antenna space division multiplexing. The method is specifically as follows: performing sampling and filtering on air interface data to obtain LTE downlink data received by a to-be-processed single antenna; using single antenna received data to perform channel estimation on two transmitting antennas Tx0 and Tx1 according to the CRS of two transmitting ports, wherein the channel estimation values are respectively hTx0 and hTx1; generating a reference planisphere for the single antenna to solve double antenna space division multiplexing data according to the single antenna received data and the channel estimation of the two transmitting ports; separating to-be-demodulated LTE data from the LTE downlink data according to the cell configuration and resource allocation conditions; inputting the separated to-be-demodulated LTE data in the generated reference planisphere, judging the minimum distance from a reference constellation point in the reference planisphere to the to-be-demodulated data to obtain to-be-decoded hard bit data; and inputting the generated hard bits into a Turbo decoder for decoding, and finally obtaining the necessary encoded bits.

A cascading error correction coder and its coding method can be used in ground data multimedia television broadcast system. It takes the error correction coding planisphere and modulation mapping planisphere as a whole to be considered to finished the net lattice coding modulation and then to realize the coding and the mapping after coding according to certain format for greatly raising the system performance in its error correction and transmission. The said net lattice coding modulation pattern can be cecular QPSK, turbo cecullar QPSK, cecullar 16 QAM, turbo cecullar 16 QAM, cecullar 64 QAM, turbo cecullar 64 QAM and etc.

The invention relates to the technical field of wireless communication, in particular to modulation and demodulation methods of enhanced 6D (six-dimensional) 64PSK (64 phase shift keying). The modulation method of the enhanced 6D 64PSK expands two 3D (three-dimensional) 8PSK planispheres to a 6D signal space via a linear block code technology, and can increase a minimum Euclidean distance between signal points in the signal space under the same mean power so as to obtain certain demodulation gain. Experiments prove that the method has a lower error rate and provides a higher-speed and higher-reliability code modulation scheme for a future wireless communication technology compared with the traditional modulation technology.

The invention discloses a wireless communication system with full diversity and a full code rate. Planisphere matching is performed on input binary digit signals on a transmitting terminal. Uniform encoding is performed on modulated plural form analog signals in a Jafarkhani coding mode. Uniform encoded data are inversely converted to composite form analog signals through Fourier transform to be output. Signals of different transmitting sets in transmitting antennas are separated through the Fourier transform on a receiving terminal, and orthogonal decoding is performed. According to the wireless communication system, a system with more than four transmitting antennas achieves the full diversity and the full code rate on the transmitting terminal and the receiving terminal respectively, and therefore properties of the whole system are improved. The wireless communication system can also use an orthogonal decoding mode, and the complexity of decoding is reduced.

The invention discloses a 16QAM system LT code modulation method, belonging to the technical field of digital communication. By studying bit likelihood ratio during belief-propagation decoding, the invention provides a new 16QAM mapping planisphere, and provides a corresponding system LT code modulation scheme. According to the code modulation scheme, good bit error rate performance can be provided by utilizing degree distribution under BPSK.

Disclosed is an 8PSK (phase shifting key) planisphere which indicates linear relation between Euclidean distance between constellations and code distance between digital codes. When the Euclidean distance between constellation points is small, code distance between digital codes is small, and the defect that smaller phase shift in a conventional planisphere leads to large number error is avoided. When Euclidean distance between the constellation points is large, code distance between digital codes is large. When Euclidean distance between the constellation points is maximum, code distance between digital codes is the maximum. Random errors on channels are in direct proportion to Euclidean distance between the constellation points, namely, random errors are gradually accumulated to result in changes of digital information. Compared with the prior art, phase change gradually increase on the premise of normal operation of the 8PSK planisphere, and change caused by information distortion of the same degree is accordant with practical information changes on random channels.