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

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.

A power control method of a multi-input multi-output space multiplexing mode is suitable for a broad band wireless orthogonal frequency division multiple access (FDMA) access system and comprises the following steps: firstly, adaptively modulating a code AMC; and then, calculating the number of ranks and conditions of a channel matrix, taking the number as the judgment basis of the strength and the weakness of the channel relativity of a plurality of received parallel data streams and respectively carrying out corresponding power adjustment according to the strength and the weakness of the channel relativity. The invention controls the power according to the strength and the weakness of the channel relativity of user channels with pertinence, especially the power control method provided byaiming at the strong channel relativity of the users can effectively prevent ineffective power control under an MIMO space multiplexing mode, thereby the anti-interference property and the anti-fading property of a system are enhanced.

A time-frequency fully averaged orthogonal multiple access transmission method based on extended weighted fractional Fourier transform belongs to the technical field of wireless communication. The invention solves the problems of poor time-frequency deep fading performance and low transmission reliability of existing multiple access systems. The present invention proposes a new orthogonal multiple access transmission method. By performing symbol mapping and extended weighted fractional Fourier transform on each user data, a signal form with time-frequency energy averaging characteristics is formed, while retaining The quadrature advantage of the original signal. In the solution proposed by the present invention, each user can occupy all the time-frequency resources available to the system without causing mutual interference. At the same time, since the proposed multiple access system achieves a uniform distribution of signals in the time-frequency plane, it has better anti-time-frequency deep fading performance, effectively improves the bit error performance under harsh channel conditions, and enhances the transmission of the multiple access system. reliability. The present invention can be applied to the technical field of wireless communication.

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.

A signal time-frequency energy complete average transmission method based on extended weighted fractional Fourier transform belongs to the technical field of wireless communication. The invention solves the problem of poor capability of dispersing and compensating channel fading in existing methods. The invention realizes the design of the extended mixed carrier signal having both time-domain energy averaging characteristics and frequency-domain energy averaging characteristics through the extended weighted fractional Fourier transform. In a fading channel, the energy loss of each symbol is shared by other symbols, and its energy is well preserved. The receiving end only needs to perform the corresponding inverse transformation to achieve signal recovery with high probability. The solution proposed by the invention greatly improves the dispersion and compensation capabilities for channel fading, effectively reduces the bit error rate under fading channels, and improves the reliability of the communication system. At the same time, the method has good compatibility with the existing communication system. The present invention can be applied to the technical field of wireless communication.

The invention provides a means of channel coding using UDI channel of PHS, it includes: coding the sound; adding the cyclic redundancy check code that is CRC code to the sound data which is after the coding; the sound coding data is convoluotinal encoding or repeat encoding [M1]; the sound data which is after the convoluotinal encoding or repeat encoding is bit slotting or filling. The invention is simple, and it increases the fading property of PHS, and increases the sound quality. Because the invention makes UDI channel possesses bearing of coding protection, so the AMR, command, VoIP can be transferred.

The invention discloses an Alamouti encoding method based on collaborative constellation mapping, and mainly solves the problems of high block error and worse anti-fading capability of an Alamouti space time code. The method comprises the following steps: dividing the bit stream of a transmitting end into three groups, generating a modulation constellation to map three groups of bits, constructing and combining a collaborative modulation symbol to obtain a transmission symbol, using the Alamouti space time code to transmit the symbol, receiving signals within two symbol periods by a receiving end and constructing a composite receiving signal vector, calculating a zero forcing detection solution vector according to the composite receiving signal vector, using a maximum likelihood estimator to perform first layer judgment on the zero forcing detection solution vector, calculating an European style and performing second layer judgment, and finally performing constellation inverse mapping on the judged result and combining the result to obtain the bit stream. By means of collaborative constellation mapping mode, a better error block function is obtained, the anti-fading capability of the system is enhanced, the communication confidentiality is strengthened at the same time, and the method can be applied to a two-transmit-antenna and one-receive-antenna system.

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 usedfor 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 setiterative 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 propertyrelative to the prior LSBC decoding method, and can be used for the space-time coding in an MIMO system.

This invention relates to a system for realizing coexistence of multimode networks including a multi-mode emitter for emitting signals after channel code, symbol mapping and modulation process simultaneously or in time-sharing by a set of emission antennas and a multi-mode receiver for receiving signals from the emitter to carry out lateral hierarchical space multiplex decode process, de-modulation, symbol de-mapping and channel decode to get signals under various network modes, besides, the two devices also include a code-decode unit of empty-time, empty-frequency and empty time frequency, in which, said base station can access said user station at the same frequency simultaneously or in time-sharing and the user station can switch among different networks movably in the soft switch mode.

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.