16 results about "High spectral efficiency" patented technology

A method, a network device, and a non-transitory computer-readable storage medium are described in relation to an MIMO selection service. The MIMO selection service may include calculating MIMO configurations that include a number of layers for each MIMO configuration pertaining to a group of end devices; and identifying performance metric sensitive end devices of the group. The MIMO selection service may further include selecting for each performance metric sensitive end device, a first MIMO configuration from the MIMO configurations that has a higher number of layers relative to one or more other MIMO configurations of the MIMO configurations; and selecting for each non-performance metric sensitive end device of the group, a second MIMO configuration from the MIMO configurations that combined with the first MIMO configuration yield a highest spectral efficiency.

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.

This invention belongs to the field of wireless communication technology and discloses a selection method for a high-spectrum-efficiency R16QAM (Rateless 16QAM) structured bit selector. First, N information bits are encoded using a 1 / 3 code rate Turbo code to obtain a 3N-length coded bit block to be transmitted. Then, the coded bit block is progressively selected in a structured manner according to the symbol transmission order, and finally transmitted and received in a rateless manner. Specifically, bits are extracted from multiple candidate sub-blocks and recombined to generate structured bit sub-blocks. Multiple bit sub-blocks constitute a single bit block, and different bit blocks are progressively generated. This structured "bit sub-block-bit block-progressive bit block" construction method reintegrates the entire coded bit block to be transmitted into a hierarchical structured block, providing the receiver with iteratively demodulated and decoded multi-dimensional correlation observation information.

The application discloses a coherent optical communication system and a sequence detection method based on LUT soft decision output, wherein at the sending end of the coherent optical communication system, binary bit stream original data is first mapped into QPSK symbols, the original QPSK signal is filtered through a narrow-band digital filter to obtain a narrow-band filtered QPSK signal, then the pre-filtered QPSK signal is Nyquist sampled to obtain a digital signal to be sent, after the sending end DSP is completed, the digital signal to be sent needs to be converted into an analog signal through a digital-to-analog converter, the analog signal is optically modulated through an optical modulator to obtain an optical domain sending signal, the optical domain sending signal is transmitted through an optical fiber to reach a receiving end, coherent optical reception is realized through a coherent receiver, a digital signal is obtained through an analog-to-digital converter, a series of receiving end DSP pretreatments are carried out, finally, a BCJR algorithm based on LUT is used to perform sequence detection on the pretreated signal to recover original data. The system can realize long-distance coherent optical communication with high transmission rate and high spectral 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 application discloses a mirror suppression mixing device with in-band self-interference cancellation capability, wherein a central station comprises a signal processing module, a 90-degree electrical coupler a, a photodetector x, a photodetector y, a polarization beam splitter and an optical power amplifier; a transmission medium is a single-mode optical fiber; a remote base station comprises a laser, a polarization controller, a polarization multiplexing-double drive-Mach-Zehnder modulator, an optical filter, a receiving antenna, a transmitting antenna, a direct current source x, a direct current source y, an electrical beam splitter a and an electrical beam splitter b, an electrical beam combiner a and an electrical beam combiner b, a 90-degree electrical coupler b, a local oscillator signal generator, an electrical attenuator and an electrical delay line. The application also provides a mirror suppression mixing method with in-band self-interference cancellation capability. The application not only can play the high spectral efficiency advantage of the in-band full duplex system, but also is not affected by the dispersion-induced power periodic fading phenomenon caused by optical fiber transmission, can effectively eliminate self-interference signals under the in-band full duplex system, and can effectively suppress the mirror interference caused by the open channel reception.

The invention discloses an efficient retransmission scheduling method and system in a time division multiple access (TDMA) system, and relates to the technical field of wireless communication. The method is dominated by a network coordinator (AP), and a superframe is divided into a main time division multiple access (TDMA) period and a shared retransmission time slot period sounding reference signal (SRS). In the main TDMA period, if no data is sent in the allocated uplink time slot, the device STA must send the NULL frame, so that the AP can reliably detect the uplink failure. And the AP detects a transmission failure event in real time when the TDMAP is carried out, incrementally constructs a retransmission scheduling table, immediately broadcasts an SRS-MAP frame after a main TDMA period is ended, and intensively executes conflict-free retransmission in an SRS period. According to the invention, the contradiction between the resource efficiency and the retransmission delay of the traditional TDMA system is solved, and the beneficial effects of high spectrum efficiency, low retransmission delay, reliable failure detection and self-adaption to network change are realized.

The invention provides a satellite communication navigation fusion multiple access signal design method based on continuous interference elimination. With the increasingly mature continuous interference elimination technology, the anti-interference capability of a satellite navigation signal and the certainty of a pseudorandom sequence used by a navigation satellite are considered at the same time; the technical complexity of simulating and removing positioning signals in received signals through the continuous interference elimination technology is lower than that of layer-by-layer decoding in non-orthogonal multiple access, and it is possible that the continuous interference elimination technology is used for communication navigation fusion waveform design. In order to give play to the advantages of the continuous interference cancellation technology on multiple access, the downlink communication service is provided for a plurality of users by using the same time-frequency resource in combination with a rate splitting multiple access strategy. A communication navigation fusion multiple access scheme is designed by considering the adaptability of a positioning information sequence and a continuous interference elimination technology, the characteristic of stability of an LEO satellite constellation global coverage signal and the high spectrum efficiency and flexibility of rate splitting multiple access.

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.

This invention discloses a time-frequency coherent optical fiber communication and sensing integrated system. The entire system includes a narrow-linewidth laser, an optical fiber coupler, a polarization controller, an IQ modulator, a coherent sensing signal generator, an optical fiber amplifier, an optical fiber circulator, optical fiber, a local oscillator, a high-speed coherent receiver, a communication data acquisition and processing module, a high-sensitivity coherent receiver, and a sensing data acquisition and processing module. The transmitted signal and the sensing detection signal are fused to form a time-frequency coherent signal, and the coherent sensing optical signal is generated by the same laser and modulator. The transmission and sensing performance of the system can be flexibly adjusted by regulating the power ratio of the transmitted signal and the sensing detection signal. The transmitted signal is detected at the remote end using a high-speed coherent receiver, and the sensing signal is obtained at the local end using zero-difference coherent detection. This invention features a highly integrated system that is simple, easy to implement, and easy to adjust; it has high spectral efficiency; and it offers flexible communication and sensing adjustments with good performance.

A near-optimal Karhunen-Loeve basis expansion modeling (KL-BEM) orthogonal time frequency space (OTFS) receiver with superimposed pilots has been proposed for high-mobility communications with Doppler spread channel. First, an initial KL-BEM channel estimation is conducted by superimposed pilots, followed by the removal of superimposed pilots from the received OTFS signal and equalisation by message passing (MP) algorithm. After that, the detected data symbols are utilized as pseudo pilots along with the superimposed pilots to refine both KL-BEM channel estimation and equalisation in an iterative manner. Simulation results confirm the superior performance of the proposed KL-BEM OTFS receiver over the prior art in terms of the mean-square-error (MSE) of channel estimation and bit error rate (BER). It also has a close BER performance to the BER lower bound obtained by assuming perfect channel estimation. It contributes to high spectral efficiency and fast convergence performance.

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.