8 results about "High spectral efficiency" patented technology

The application relates to the field of optical communication technology, and provides a four-level modulation receiving device and method based on double-polarization double-binary superposition, which comprises a transmitting module, a transmission link and a receiving module; the transmitting module is used for outputting a first binary baseband signal, outputting a first three-level double-binary electrical signal, outputting a second binary baseband signal, outputting a second three-level double-binary electrical signal, performing polarization orthogonal superposition on the first three-level double-binary electrical signal and the second three-level double-binary electrical signal, and outputting one superimposed optical signal; the transmission link is used for transmitting the one superimposed optical signal; and the receiving module is used for receiving the one superimposed optical signal and restoring the one superimposed optical signal into the first binary baseband signal and the second binary baseband signal. The application realizes effective unification of high dispersion tolerance and high spectral efficiency by superimposing two double-binary signals on orthogonal polarization states.

This invention discloses an HPAM-DMT-NOMA method based on time-domain preprocessing, comprising: At the transmitting end, PAM modulation is performed on the input user transmission bits to generate PAM symbols; after power superposition, serial-to-parallel conversion, and Hermitian symmetry, the symbols are allocated to two signal components for HPAM-DMT transmission; the frequency domain signals of PAM-DMT and RPAM-DMT are calculated; an IFFT operation is performed to obtain the time domain signal; the time-domain preprocessed signal is calculated; the RPAM-DMT time domain signal is calculated and superimposed on the clipped PAM-DMT signal for synchronous transmission to obtain a mixed signal; a reconstructed signal is introduced, processed, and input to drive an LED for illumination; at the receiving end, the received signal is processed to generate a frequency domain signal, and finally, the multi-user signal is recovered. This scheme eliminates clipping noise interference between the mixed signal components, avoids error propagation problems, and achieves high spectral efficiency and power efficiency.

A system comprises a decision logic module, a payload IC, an optical transceiver, a mmWave transceiver, and an antenna array. The decision logic module evaluates channel conditions and selects one of four transmission modes based on a signal quality indicator. The payload IC generates baseband data and receives demodulated data. The optical transceiver, coupled to the decision logic and payload IC, transmits and receives optical signals via a free-space link using either a first or second modulation format. The optical array handles optical signal emission and reception. The mmWave transceiver, coupled to the decision logic and payload IC, transmits and receives mmWave signals via a free-space mmWave link using a third or fourth modulation format. The antenna array supports mmWave emission and reception. The first modulation format offers higher spectral efficiency than the second. The third provides a higher data rate than the fourth under favorable signal-to-noise conditions.

A system for satellite communications includes a decision logic module, a payload integrated circuit, an optical transceiver, an optical array, a millimeter wave transceiver, and an antenna array. The decision logic module evaluates channel conditions and selects one of four transmission modes based on a signal quality metric. The payload integrated circuit generates outbound baseband data and receives demodulated data. The optical transceiver is coupled to the decision logic module and transmits and receives optical signals over a free space link using a first or second modulation format. The optical array is responsible for optical signal transmission and reception. The millimeter wave transceiver is coupled to the decision logic module and transmits and receives millimeter wave signals over a free space millimeter wave link using a third or fourth modulation format. The antenna array supports millimeter wave transmission and reception. The first modulation format requires a higher signal-to-noise ratio and provides a higher spectral efficiency than the second modulation format, and the third modulation format requires a higher signal-to-noise ratio and provides a higher data rate than the fourth modulation format.

The present disclosure relates to a communication method, a communication device, a communication system, a storage medium and a program product. The communication method comprises: a terminal sending first information, wherein the first information corresponds to a first resource, which overlaps a second resource, the second resource being a resource corresponding to a first demodulation reference signal (DMRS) sent by the terminal. The present disclosure can obtain higher spectral efficiency and throughput.

The application discloses a visible light communication transmission method of mixed VOOK and restructured hierarchical OFDM, which comprises the following steps: generating a time domain signal of VOOK according to a code word of VOOK; generating a time domain signal of hierarchical OFDM by layering subcarrier numbers; generating a reconstruction signal according to the time domain signal of VOOK; superimposing the time domain signal of VOOK, a frequency domain signal of hierarchical OFDM and the reconstruction signal to generate a VLC transmission signal; inputting the VLC transmission signal into an LED after digital-to-analog conversion for illumination and communication transmission; converting the received communication transmission signal into an electrical signal through a photoelectric detection device at a receiving end; and performing signal detection of VOOK and hierarchical OFDM in parallel after IFFT operation and frequency domain equalization. The application effectively improves the spectral efficiency of transmission, realizes the dual functions of efficient spectral transmission and dimming control, avoids the dependence of signal detection of hierarchical OFDM on the dimming level of VOOK, has higher spectral efficiency, and effectively reduces the receiving complexity and processing time delay.

The application discloses a water acoustic MIMO communication multi-channel different carrier frequency offset two-stage joint estimation method and relates to the technical field of water acoustic communication. In view of the problem that the estimation performance is reduced due to model mismatch in the multi-channel different CFO scene, the method adopts a coarse-precise two-stage estimation framework: in the coarse estimation stage, the minimum cost function value is searched to determine and compensate the multi-channel consistent CFO component through candidate CFO compensation, tentative channel estimation and equalization; in the fine estimation stage, the multi-channel different residual CFO and the channel are jointly estimated based on the sparse Bayesian learning technology, and a low-complexity closed-form solution is obtained through Taylor series expansion by using the small characteristic of the residual CFO. The application does not need to configure zero subcarriers, effectively solves the model mismatch problem while maintaining high spectral efficiency, reduces the estimation difficulty, improves the CFO estimation precision, and is suitable for actual water acoustic MIMO-OFDM communication systems.

The application provides a self-adaptive multi-level coding transmission method, device and electronic equipment. In a transmitting end, a modulation coding scheme identifier is used to perform multi-level coding modulation according to a pre-constructed offline parameter table. In a receiving end, a same modulation coding scheme identifier is used to perform demodulation and decoding according to a corresponding multi-level coding modulation structure. The structure retains the ability of the MLC coding modulation structure to finely allocate code rates to match channels, and can realize higher spectral efficiency compared with the BICM coding modulation architecture. On the other hand, when demodulating and decoding in the receiving end, the multi-level coding structure has a local parallel feature, so that the time delay of demodulation and decoding can be reduced, and the low throughput of the MLC coding modulation structure can be improved to a certain extent.