47results about How to "Improve anti-fading performance" patented technology

The invention discloses a short-wave multi-antenna signal enhancement receiving method. The method comprises the following steps: firstly, adding cyclical redundancy check (CRC) bits for sent information bits at a sending end, forming a data block through modulation after channel coding and interleaving processing, and adding a synchronous sequence for a receiving end to extract timing synchronous information before the data block is sent; adopting multi-antenna receiving when the receiving end receives signals, utilizing received signals to extract the synchronous information, simultaneously carrying out channel estimation, and estimating corresponding channel parameters for demodulation processing; after carrying out one-by-one antenna demodulation or one-by-one path demodulation on multi-path signals received from different antennas, and carrying out diversity combination; using parallel data after diversity combination to solve a soft bit value, after deinterlacing and decoding decision, obtaining all paths of data by sequential checking and decoding of CRC, and when checking that certain path of data is correct, stopping checking, and simultaneously outputting the path of data. By utilizing the short-wave multi-antenna signal enhancement receiving method, the receiving performance of a short-wave fixed station is improved, and the anti-fading performance of the existing short-wave communication system is enhanced.

This invention discloses a distributed mutual transfer method and a system, in which, said method includes: a mutual node set transfers radio communication data of the mutual nodes to the objective node by the MIMU technology, said objective node receives and MIMU coding radio communication data from said mutual nodes, said system includes: a mutual node set and an objective node, in which, said mutual node set is composed of at least two mutual nodes and transfers radio communication data of the nodes to the objective node used in receiving and MIMU coding radio communication data from the mutual nodes.

The invention discloses a method for distributing RBGs (resource block groups) in an LTE (long term evolution). The method comprises the following steps that: RBGs in a time slot 1 and/or time slot 2 are distributed for a terminal sending CQI (channel quality indicator) information, according to the received CQI information and recorded RBG use conditions, and the RBG distribution result is compiled in DCI (downlink control information) in a new DCI form. The invention also discloses a device for distributing RBGs in the LTE. According to the invention, RBGs are respectively distributed for two time slots of a common frame according to the signal conditions of the two time slots in the common frame, so as to improve the anti-fading property of the LTE, thereby further enhancing the performance of the whole system.

The invention discloses a coal mine under-well ultra-wide band locating method and a coal mine under-well ultra-wide band locating system. The method comprises the following steps: by adopting a RAKE receiver technology, collecting multipath components in signals, and weighing the multipath components; performing non-line-of-sight identification on the signals by utilizing the constructed identification parameters, performing data reconstruction on the non-line-of-sight signals, and performing location calculation by adopting a Taylor sequence expansion method and utilizing the reconstructed data and line-of-sight signals. The system comprises a well-surface part and an under-well part. The well-surface part comprises a ground monitor terminal, a locating server, a central switch, a dynamic host configuration protocol server, and an upper layer terminal; the under-well part comprises an intrinsically safe gateway, an intrinsically safe direct current power supply, an intrinsically safe wireless relay station, an intrinsically safe reference point terminal and an intrinsically safe locating terminal. The ultra-wide band locating method and the ultra-wide band locating system are simple in structure, accurate in positioning and strong in anti-jamming ability, can effectively inhibit multipath effect and non-line-of-sight effect, and meet use requirements of the mine.

The invention discloses an OFDM-IM modulation method for transmission diversity, and mainly solves the problem that the bit-error performance is low in the prior art. The technical scheme comprises the following steps of: (1), performing OFDM-IM frequency-domain signal design of the transmission diversity, so that a frequency-domain signal is obtained; (2), performing OFDM modulation and block interleaving of the frequency-domain signal, so that a modulated signal is obtained; (3), transmitting the modulated signal in a channel, so that a received signal is obtained; (4), performing OFDM demodulation and de-interleaving of the received signal by a receiving end, so that a demodulated signal is obtained; (5), detecting the demodulated signal by the receiving end, so that an estimated signal is obtained; and (6), inversely mapping the estimated signal into bit information, so that a signal transmission process is completed. By means of the OFDM-IM modulation method disclosed by the invention, the transmission diversity gain can be obtained; compared with the traditional OFDM-IM, the OFDM-IM modulation method has relatively high anti-fading capability and better bit-error performance, and can be used for improving the error code performance of a wireless communication system; and thus, reliable transmission is realized.

The invention relates to an encryption algorithm of encryption OFDM (Orthogonal Frequency Division Multiplexing) based on discrete Hartley transform, and belongs to the technical fields of information communication and signal processing. Compared with the conventional OFDM system, an IFFT (Inverse Fast Fourier Transform) module which is necessary in an OFDM system is omitted, and the complexity of the system is reduced. At the same time, the diversity gain of frequency selectivity of the system is increased, and the anti-fading performance and the capacity of the system are improved.

The invention relates to an LTE transmission and coverage system for achieving FTTH based on the digital technology. The LTE transmission and coverage system for achieving FTTH based on the digital technology is characterized by comprising near-end equipment and far-end equipment, wherein the near-end equipment comprises a near-end duplexer/time slot switch switchover unit, an LTE near-end down link, an LET near-end up link and a near-end digital signal processing unit, the far-end equipment comprises a far-end digital signal processing unit, an LTE far-end down link, an LTE far-end up link and a far-end duplexer/time slot switch switchover unit, the near-end digital signal processing unit communicates with the far-end digital signal processing unit through optical fibers, the near-end equipment is further connected with an LTE signal source, and the far-end equipment is further connected with a transmit-receive antenna. The LTE transmission and coverage system for achieving FTTH based on the digital technology is stable in performance, high in antijamming performance, high in anti-fading performance, high in safety and far in transmission distance, saving network cost and the like.

The invention discloses a method for receiving and transmitting signals. The method comprises the steps of distributing bit information produced by a signal source to a plurality of transmitting antennas, and encoding and modulating the bit information distributed to all transmitting antennas respectively; conducting spatial interleaving and Q-channel interleaving on all channels of encoded and modulated modulating symbols respectively; conducting pre-coding on all channels of symbols after the Q-channel interleaving, and then sending symbols through antennas respectively; receiving a plurality of channels of receiving symbols, and conducting pre-decoding on all channels of receiving symbols respectively; conducting Q-channel de-interleaving and spatial de-interleaving on all channels of symbols subjected to pre-decoding respectively; and demodulating and decoding all channels of symbols after the spatial de-interleaving. The invention also discloses a system for receiving and transmitting signals and related devices correspondingly. By the aid of the method, the system and related devices, the high transmission efficiency of the system can be achieved, the spectrum utilization efficiency can be improved, the transmission reliability can be improved through diversities, the wireless system anti-fading performance can be greatly improved, and the requirements for development of wireless transmission networks can be met.

The invention discloses a weighted fractional Fourier transform time domain two-component signal interleaving transmission method, and belongs to the technical field of wireless communication. According to the invention, the problem of poor channel fading resistance of the existing single carrier communication method is solved. The invention designs a signal transmission method of an extended transform domain for an existing single carrier communication system, and an energy averaged signal form is formed for communication transmission by interleaving two component signals of a time domain. Because the energy of a single symbol and other multiple symbols are mixed and expanded in the process, an effect of relatively more uniformly distributing the signal energy in a time-frequency plane isachieved, the energy loss caused by channel fading is averaged to multiple symbols, the probability of distortion of a high-power signal is greatly reduced, the bit error rate under a fading channelis effectively reduced, and the reliability of the system is improved. The present invention can be applied to the technical field of wireless communications.

The invention discloses a decoding method based on iterative layer space-time group codes, which comprises the following steps: firstly, grouping channel matrixes and receiving vectors according to the grouping number of an antenna; secondly, performing the group interference suppression to each group of receiving vectors, and performing the STBC decoding to the obtained modified receiving vectors to obtain each group of non-iterative decoding result; thirdly, feedbacking the result to a receiving terminal for performing the STBC decoding again to obtain each group of new decoding matrix used for eliminating the interference of the receiving terminal to decode a certain of group of receiving vectors; fourthly, performing the STBC decoding to the receiving vectors after being eliminated with the interference again, and feedbacking each group of obtained iterative decoding result to the receiving terminal; fifthly, repeating the step 3 and the step 4 for n-1 time(s) according to the set iterative time n, and performing the parallel-to-serial conversion to each group of decoding result iterated by n times to obtain the final decoding result. The invention has high antifading property relative to the prior LSBC decoding method, and can be used for the space-time coding in an MIMO system.

The invention discloses a transmitting method for a constant envelope frame synchronization signal, comprising the following steps of: respectively modulating a segment of constant envelope sampling point sequence (FORMULA referred) with a sampling rate as FS at a frequency F and a frequency F+deltaF, and respectively obtaining modulated sequence (FORMULA referred) and sequence (FORMULA referred),wherein the sampling point sequence includes M constant envelope sampling points, the transmission time corresponding to the first point of the sequence(FORMULA referred) is (FORMULA referred), the transmission timing corresponding to the first point of the sequence (FORMULA referred) is (FORMULA referred), and the sequences (FORMULAE referred) are combined to obtain the constant envelope frame synchronization signal (FORMULA referred). The synchronization signal provided by the invention has a multi-segment structure, and the number of segments can be controlled and distributed over different frequencies. By using the frequency diversity, the time overhead can be reduced with the same false synchronization or miss synchronization probability compared to other synchronization signals.

The invention discloses an OFDM signal transmission method for expanding hybrid carrier precoding, and belongs to the technical field of wireless communication. According to the invention, the problem that the existing multi-carrier communication method is poor in channel fading resistance under the condition of time-frequency double fading channels is solved. The invention designs a signal transmission method of an extended transform domain for an existing multicarrier communication system, and by performing extended hybrid carrier precoding on a modulated signal in front of an IDFT module, an extended hybrid carrier precoded OFDM signal with an energy averaging characteristic can be obtained. Under the channel condition with time dispersion, due to equalization processing on channel fading, the probability of complete loss of signal energy due to deep attenuation is greatly reduced, so that a receiving end can recover an original signal, a system has better error code performance, and the communication reliability of a multi-carrier system is effectively improved. Meanwhile, the method has good compatibility with other existing multi-carrier communication methods. The present invention can be applied to the technical field of wireless communications.

The invention discloses a multi-carrier system anti-fading method based on fractional order C transformation, and the method is characterized by comprising the following steps: 1) inputting data, carrying out the constellation mapping, and carrying out the serial-parallel conversion; 2) adding a cyclic prefix after inverse transformation of the fractional order C transformation, and performing parallel-serial conversion; 3) performing serial-to-parallel conversion after passing through a dual-selectivity fading channel, and removing a cyclic prefix; 4) carrying out fractional order C transformation and carrying out constellation inverse mapping after serial-parallel conversion to obtain output data; and 5) performing performance analysis. According to the method, the influence of inter-symbol interference ICI and inter-subcarrier interference ISI is reduced, the influence of the peak-to-average power ratio is reduced, and the anti-fading performance of the system is improved.