Abstract: The present disclosure provides an N protein epitope mutation marker for preparing an epitope deletion-marked vaccine strain of type II porcine reproductive and respiratory syndrome virus (PRRSV) and use thereof, belonging to the technical field of biological products. In the mutation marker, one or more amino acids are mutated based on an epitope sequence at positions 92 to 103 of a C-terminal of an N protein of the type II PRRSV; and the epitope mutation marker has an amino acid sequence shown in SEQ ID NO: 1, where X1 is selected from the group consisting of T, P, and A; and X2 is selected from the group consisting of V and A.

Abstract: A die-casting aluminum alloy without heat-treatment and a preparation method and application thereof. Based on a total weight of the die-casting aluminum alloy, the die-casting aluminum alloy includes: 6.0 to 8.0 wt % of Si; 0.3 to 1.2 wt % of Mg; 0.4 to 0.8 wt % of Cu; 0.1 to 0.3 wt % of Fe; 0.6 to 0.8 wt % of Mn; 0.05 to 0.20 wt % of Ti; 0.03 to 0.07 wt % of Sr; 0.03 to 0.07 wt % of Ce; 0.01 to 0.04 wt % of La; 0.01 to 0.1 wt % of Zr; less than or equal to 0.01 wt % of other impurity elements; and a balance of Al.

Abstract: Power systems including converters that exhibit reduced common mode voltage emissions are described. In one example, a power converter system includes an input and an output, a multi-level switch bridge coupled between the input and the output, an input capacitor branch coupled across the input, an output capacitor branch coupled across the output, and a controller configured to generate switching control signals for the multi-level buck-boost switch bridge. The multi-level switch bridge also includes a plurality of inductors in one example. In one case, a quadrangular or quadrangle control mode can be relied upon to switch the multi-level switch bridge, to minimize the ripple in the inductors, achieve zero voltage switching, reduce common mode electromagnetic interference emission by the converter, and for other benefits.

Abstract: A mobile multimedia broadcast transmission system is provided, which comprises: a Reed-Solomon (RS) coding and byte interleaving unit, a Low Density Parity Check (LDPC) coder, a bit interleaver, a constellation mapping unit, a frequency domain symbol generator, a scrambler, an Inverse Fast Fourier Transform (IFFT) unit, a time domain framing unit, and a transmitter. According to the technical solutions provided in the present invention, the system can provide high-quality mobile multimedia services for users in a 6 MHz operation bandwidth. Furthermore, an optimized selection is performed on RS coding according to the operation bandwidth of the system, thereby selecting an appropriate coding mode according to different channel conditions. Accordingly, the byte interleaver is optimized, such that suitable interleaving parameters can be used to perform byte interleaving.

Abstract: The present invention discloses a multi-carrier digital multimedia broadcast system and the digital information transmission method thereof. After RS encoding and byte interleaving, LDPC encoding, bit interleaving and constellation mapping to an upper layer of data streams in turn, the obtained data symbol is multiplexed with scattered pilots and continual pilots which include the system information to form an OFDM frequency domain symbol and scrambled; an OFDM time domain symbol is generated by IFFT transforming, and after inserted with the frame head to build a time slot, it is connected to form a signal frame of the physical layer; the signal frame of the physical layer is transmitted after being low-pass filtered and orthogonal upconverted. The system and method thereof provide wireless broadcast with high quality such as audio, video and multimedia data and the like for mobile, fixed and portable receivers, and can use the satellite transmission and terrestrial transmission method for transmitting.

Abstract: The present invention provides a method for transmitting/receiving a continuous pilot code in a multi-carrier system. The method for transmitting comprises: performing a time-frequency domain two dimensional encoding on an information bit stream to be transmitted; mapping the encoded bit stream to obtain a continuous pilot carrying encoding information; multiplexing a load, a discrete pilot and the mapped continuous pilot carrying the encoding information based on distribution of the load, the discrete pilot and the continuous pilot on a sub-carrier, to generate a frequency domain signal; and performing a frequency-time domain transforming on the generated frequency domain signal, to obtain a time domain sample. The method for receiving comprises: extracting the continuous pilot from an active carrier of a multi-carrier signal; and performing a time-frequency domain decoding on the extracted continuous pilots to obtain the decision of transmitted information bits.

Abstract: The present invention relates to a method for constructing LPDC code check matrix and encoding and decoding devices using the same. The present invention constructs the LDPC code check matrix using an algebraic structure, obtaining the LDPC code with stable performance.

Abstract: An efficient general QC-LDPC code decoder includes a general-purpose processor for distributing the storage storage space of the data memory block, and establishing an index for data addressing; a data memory block for storing the information used during decoding; a hardware accelerator for conducting part or all of the information processing operations including parity check, check node updating and variable node updating. A corresponding QC-LDPC code decoding method includes initializing the variable node information and performing parity check on the check matrix row block by row block; updating the check node row block by row block and updating the variable node column block by column block if any check equation is not met.

Abstract: The embodiments of the present invention provide a method of constructing parity-check matrix of LDPC code. The method comprises the following steps of: constructing a MB×NB base matrix B for an LDPC code with code rate R and code length N, wherein MB=M/K, NB=N/K, M=N (1?R), K is the expansion factor of the base matrix, K??, and ? is the set of the common factors of M and N; and replacing the elements of the base matrix B with a K×K matrix, and expanding the base matrix B into a parity-check matrix H with size of M×N for the encoding or decoding of the LDPC code. An encoding method and apparatus of LDPC code are also provided by the embodiments of the present invention. The technical solutions provided by the embodiments of the present invention can construct LDPC codes with good performance, solve the storage problem of the parity-check matrix, and effectively reduce the implementation complexity of the encoding apparatus.

Abstract: A system and method for generating and detecting identifier sequence of a bandwidth-limited transmitter are disclosed, comprising an identifier sequence generating portion and a detection portion. The identifier sequence generating portion comprises: generating a frequency-domain random sequence; generating a frequency-domain orthogonal sequence; performing frequency-domain truncation; performing frequency-time transformation; and performing cycle extension.

Abstract: A mobile multimedia broadcast transmission system is provided, which comprises: a Reed-Solomon (RS) coding and byte interleaving unit, a Low Density Parity Check (LDPC) coder, a bit interleaver, a constellation mapping unit, a frequency domain symbol generator, a scrambler, an Inverse Fast Fourier Transform (IFFT) unit, a time domain framing unit, and a transmitter. According to the technical solutions provided in the present invention, the system can provide high-quality mobile multimedia services for users in a 6 MHz operation bandwidth. Furthermore, an optimized selection is performed on RS coding according to the operation bandwidth of the system, thereby selecting an appropriate coding mode according to different channel conditions. Accordingly, the byte interleaver is optimized, such that suitable interleaving parameters can be used to perform byte interleaving.

Abstract: The present invention relates to the field of communication technology. A channel estimation device for an Orthogonal Frequency Division Multiplexing (OFDM) system is provided for performing channel estimation on data based on synchronization signal and pilot, which comprises: a synchronization signal based initial channel estimation module for performing initial channel estimation based on a synchronization signal in the data; a pilot channel tracking module for performing pilot channel tracking on the result of the initial channel estimation; a noise reduction module for performing noise reduction on the result of the pilot channel tracking; and an effective sub-carrier extraction module for extracting channel estimation values of effective sub-carriers from the result of the noise reduction.

Abstract: The present invention relates to a method for constructing LPDC code check matrix and encoding and decoding devices using the same. The encoding device encodes the inputted binary information and outputs the encoded system code sequence of position transformation. The encoding device comprises: a matrix multiplication module outputting a check sequence p which is obtained through the binary information sequence m multiplied with a matrix; a sorting index module having N memory units storing index values of a sorting table IDX in turn; and a sorting output module for sorting the m and p and outputting a code word c based on the index value stored in the sorting index table. The present invention constructs the LDPC code check matrix using an algebraic structure, obtaining the LDPC code with stable performance. In addition, the encoding and decoding devices of the present invention occupy less memory, which is preferable for optimization of the devices.

Abstract: A method for transmitting control information to indicate a receiver, comprising following steps: the control information is formed at transmitting side and is encoded based on the working status of the transmitting side of the system; after the encoded control information is mapped, it is multiplexed with other pilot symbol and service load, then an OFDM symbol is generated; the OFDM symbol is transformed from frequency domain to time domain, then a time domain sampling signal is obtained and transmitted to the receiving side of the system; at the receiving side, the time domain sampling signal transmitted by the transmitting side is received and transformed from time domain to frequency domain to form OFDM symbol; the control information is obtained from the valid sub carrier of the OFDM symbol, and the control information is decoded; each work information is extracted form the decoded control information, and the receiving terminal is indicated to execute respective receive process based on the extracted w

Abstract: The present invention discloses a multi-carrier digital multimedia broadcast system and the digital information transmission method thereof. After RS encoding and byte interleaving, LDPC encoding, bit interleaving and constellation mapping to an upper layer of data streams in turn, the obtained data symbol is multiplexed with scattered pilots and continual pilots which include the system information to form an OFDM frequency domain symbol and scrambled; an OFDM time domain symbol is generated by IFFT transforming, and after inserted with the frame head to build a time slot, it is connected to form a signal frame of the physical layer; the signal frame of the physical layer is transmitted after being low-pass filtered and orthogonal upconverted. The system and method thereof provide wireless broadcast with high quality such as audio, video and multimedia data and the like for mobile, fixed and portable receivers, and can use the satellite transmission and terrestrial transmission method for transmitting.

Abstract: A system and method for generating and detecting identifier sequence of a bandwidth-limited transmitter are disclosed, comprising an identifier sequence generating portion and a detection portion. The identifier sequence generating portion comprises: generating a frequency-domain random sequence; generating a frequency-domain orthogonal sequence; performing frequency-domain truncation; performing frequency-time transformation; and performing cycle extension.

Abstract: An efficient general QC-LDPC code decoder includes a general-purpose processor for distributing the storage space of the data memory block, and establishing an index for data addressing; a data memory block for storing the information used during decoding; a hardware accelerator for conducting part or all of the information processing operations including parity check, check node updating and variable node updating. A corresponding QC-LDPC code decoding method includes initializing the variable node information and performing parity check on the check matrix row block by row block; updating the check node row block by row block and updating the variable node column block by column block if any check equation is not met.

Abstract: A method for transmitting control information to indicate a receiver, comprising following steps: the control information is formed at transmitting side and is encoded based on the working status of the transmitting side of the system; after the encoded control information is mapped, it is multiplexed with other pilot symbol and service load, then an OFDM symbol is generated; the OFDM symbol is transformed from frequency domain to time domain, then a time domain sampling signal is obtained and transmitted to the receiving side of the system; at the receiving side, the time domain sampling signal transmitted by the transmitting side is received and transformed from time domain to frequency domain to form OFDM symbol; the control information is obtained from the valid sub carrier of the OFDM symbol, and the control information is decoded; each work information is extracted form the decoded control information, and the receiving terminal is indicated to execute respective receive process based on the extracted w

Abstract: The present invention provides a method for transmitting/receiving a continuous pilot code in a multi-carrier system. The method for transmitting comprises: performing a time-frequency domain two dimensional encoding on an information bit stream to be transmitted; mapping the encoded bit stream to obtain a continuous pilot carrying encoding information; multiplexing a load, a discrete pilot and the mapped continuous pilot carrying the encoding information based on distribution of the load, the discrete pilot and the continuous pilot on a sub-carrier, to generate a frequency domain signal; and performing a frequency-time domain transforming on the generated frequency domain signal, to obtain a time domain sample. The method for receiving comprises: extracting the continuous pilot from an active carrier of a multi-carrier signal; and performing a time-frequency domain decoding on the extracted continuous pilots to obtain the decision of transmitted information bits.