477 results about "Higher-order modulation" patented technology

A random code length polar encoding method includes: during construction of a polar code, if the code length is not the power of 2, using a group of virtual channels with the capacity of zero for supplementing the channel number to be the power of 2; performing mixed mapping for each channel according to the capacity equalization principle; and performing polar conversion for the obtained channels, selecting the channels with higher capacity from converted channels according to the designed bitrate for transmitting information bit sequences, and using the rest channels for transmitting a known fixed bit sequence of a receiving end and a transmitting end. The method enables polar encoding to allow the code length to be an optional positive integer and is applicable to multi-carrier and high-order modulation systems, and the added perforating operation enables the encoding bit sequences outputted by an encoder to be optional in length; by means of channel mixed mapping, polar encoding can adapt to different component channels of parallel channels, so that anti-noise performance is good; and flexibility of using polar codes for a practical digital communication system is greatly improved, and accordingly the method has good application prospect.

A discrete multitone stacked-carrier spread spectrum communication method is based on frequency domain spreading including multiplication of a baseband signal by a set of superimposed, or stacked, complex sinusoid carrier waves. In a preferred embodiment, the spreading involves energizing the bins of a large Fast Fourier transform (FFT). This provides a considerable savings in computational complexity for moderate output FFT sizes. Point-to-multipoint and multipoint-to-multipoint (nodeless) network topologies are possible. A code-nulling method is included for interference cancellation and enhanced signal separation by exploiting the spectral diversity of the various sources. The basic method may be extended to include multielement antenna array nulling methods for interference cancellation and enhanced signal separation using spatial separation. Such methods permit directive and retrodirective transmission systems that adapt or can be adapted to the radio environment. Such systems are compatible with bandwidth-on-demand and higher-order modulation formats and use advanced adaptation algorithms. In a specific embodiment the spectral and spatial components of the adaptive weights are calculated in a unified operation based on the mathematical analogy between the spectral and spatial descriptions of the airlink.

A wireless communication device (‘device’) is configured to generate an OFDM/A packet that includes at least one OFDM/A symbol that includes at least one SIG having SIG information modulated on only even (or odd) sub-carriers and does not include any information modulated on odd (or even) sub-carriers of a set of OFDM/A sub-carriers. The set of OFDM/A sub-carriers may be all or less than all of available sub-carriers. The device may generate the packet to include a preamble and a payload such that the payload, which may be composed of at least one additional OFDM/A symbol, includes data modulated on some or all of the sub-carriers of the set of OFDM/A sub-carriers. The device can modulate and transmit SIG information and data differently within the preamble and the payload (e.g., with higher ordered modulation or MCS for the data and less power per sub-carrier than for the preamble).

A system employs space-time coding characterized at the transmitter by bit-interleaved coded modulation (BICM) combined with modulating several streams of the BICM encoded data for transmission over two or more antennas. Space-time coding techniques improve transmission efficiency in radio channels by using multiple transmit and/or receive antennas and coordination of the signaling over these antennas. Bit-interleaved coded modulation provides good diversity gain with higher-order modulation schemes that employ binary convolutional codes. A receiver demodulates the received signals and applies multi-input, multi-output (MIMO) demapping to estimate the BICM encoded bitstream. After deinterleaving of the BICM encoded bitstream, maximum a posteriori (MAP) decoding is applied to the resulting bit stream to generate soft output values. By applying well-known turbo-decoding principles to iteratively demap and decode, the overall receiver performance is significantly improved. The MIMO demapping and MAP decoding processes exchange likelihood information to improve the bit error rate performance over several iterations of demapping/decoding. By generating tentative decisions for transmitted bits, the overall number of evaluations used for demapping may be reduced.

A transmitting device, a receiving device, an optical communication system, and associated methods are provided. The transmitting device transmits an optical signal containing data, and comprises: an optical tone generator for generating at least one optical tone; at least one encoder for performing advanced coding on at least one data signal respectively, each of the at least one data signal carrying a part of the data; at least one mapper for performing high order modulation on the at least one coded data signal; and an up-converter for up-converting the at least one high-order-modulated data signal into the optical signal to be outputted through the at least optical tone. Thereby, high speed (e.g., over 1-Tb/s) transmission per single channel over a long-haul distance (e.g. over 1000-km) with error-free recovery may be achieved.

According to one embodiment of the invention, a 16-QAM optical modulator has a Mach-Zehnder modulator (MZM) coupled to a drive circuit that drives the MZM based on two electrical binary signals. The output of the MZM corresponds to an intermediary constellation consisting of four constellation points arranged on a straight line in the corresponding in-phase/quadrature-phase (I-Q) plane. Two of these constellation points correspond to a zero phase, and the remaining two constellation points correspond to a phase of π radian. The 16-QAM optical modulator further has a phase shifter that modulates the output of the MZM based on two additional electrical binary signals. The resulting optical output signal corresponds to a star 16-QAM constellation, which is produced by incremental rotation of the intermediary constellation.

A method for prioritizing protection in the symbol mapping of selected information includes the steps of supplying information bits and overhead bits. Interleaving the information bits and overhead bits to supply a plurality of interleaved data blocks. And selectively mapping the plurality of interleaved data blocks into a modulation symbol.

The invention discloses a polar code encoding modulation method applicable to any high-order modulation. The method comprises the concrete steps of (1), calculating the code length of a polar code; (2), generating an encoding matrix of the polar code; (3), generating the encoding matrix after puncturing; (4), generating code words of the polar code; (6) interleaving the code words; and (7), carrying out high-order modulation. According to the method, the code words are interleaved by employing a grouping interleaving technology, the polar effect of a channel is intensified with the combination of the polar characteristic of the polar code itself and the capacity differences of high-order modulation sub-channels, and the performance of the polar code is improved. According to the method, the encoding matrix is punctured according to a column weight, the decoding delay is reduced, and the programming realization complexity of a decoding algorithm in a programmable device is reduced. The flexibility of the polar code in the high-order modulation is improved, and the polar code has good performance.

A system employs space-time coding characterized at the transmitter by bit-interleaved coded modulation (BICM) combined with multi-carrier Orthogonal Frequency Division Multiplexing (OFDM) modulation. Space-Time coding techniques improve transmission efficiency in radio channels by using multiple transmit and/or receive antennas and coordination of the signaling over these antennas. Bit-interleaved coded modulation provides good diversity gain with higher-order modulation schemes that employ binary convolutional codes. OFDM modulation allows for wideband transmission over frequency selective radio channels. A receiver demodulates the OFDM signal and applies multi-input, multi-output (MIMO) demapping to estimate the BICM encoded bitstream. After deinterleaving of the BICM encoded bitstream, maximum a posteriori (MAP) decoding is applied to the resulting bit stream to generate soft output values. The MIMO demapping and MAP decoding processes exchange likelihood information to improve the bit error rate performance over several iterations of demapping/decoding. By applying well-known turbo-decoding principles to iteratively demap and decode, the overall receiver performance is significantly improved.

The invention provides a synchronized method of an orthogonal frequency division multiplexing (OFDM) system. The invention discloses an associated synchronized method of frame synchronization, carrier frequency synchronization and sampling clock synchronization. Carrier frequency offset estimation, channel estimation and fine estimation of symbol timing offset are performed again after sampling clock offset correction is finished, thereby avoiding influences of sampling clock offset on the carrier frequency offset estimation, the channel estimation and the fine estimation of the symbol timing offset, compensating phase deflection caused by the residual carrier frequency offset and the sampling clock offset simultaneously, greatly improving the synchronized performance, and meeting the demands of a high-order modulated system. In addition, due to aiming at a low time-varying channel, the channel estimation is required to be performed once only, thereby reliving the complexity of the system.

The present application relates to the field of wireless communications, and in particular, to an indication method and device for a modulation coding scheme. It is for solving the problem that in an existing LTE/LTE-A system, a higher-order modulation scheme cannot be supported, thereby limiting the further improvement of throughput in an application scenario of a high signal-to-noise ratio. The method of the embodiments of the present application includes: according to the channel quality and a first MCS table, a network side determining an MCS level corresponding to a channel scheduled for a UE; and by means of first indication information, notifying the UE of the determined MCS level, so as to indicate to the UE to determine a modulation scheme and code rate for the channel scheduled therefor according to the MCS grade, wherein there are at least corresponding entries of MCS indexes and TBS indexes corresponding to modulation schemes at higher modulation orders than 6 in the first MCS table. The embodiments of the present application introduce a higher-order modulation scheme into an existing LTE/LTE-A system, improving the spectrum efficiency.

Embodiments of a radio link control media access control module and associated methods may be described herein. Other embodiments may be described and claimed.

A reception method and receiver structure that are relatively simple, that have close to optimum performance, and that use high order modulation combined with a low spreading factor are disclosed. The method receives a signal transmittal in the form of sequences of coded binary symbols comprising both predefined pilot symbols and date symbols multiplied by a spreading sequence. The method also includes a step of determining a channel estimate using received predefined pilot symbols. A system for receiving a signal transmitted on a multipath transmission channel using a spread spectrum technique and low spreading factor is also disclosed.

A method (100) for simplifying soft-decision metric decisions in a M-ary modulation system includes determining (102) a single function for a soft-decision metric for each bit in a symbol by restricting the set of all possible Gray-coded constellation points to those closest to a boundary between a bit value of 0 and 1 for each bit in the input symbol and applying a predetermined function corresponding to the range of restricted constellation points to the entire possible range of symbols. A next step includes inputting (104) a symbol having real part, x, and an imaginary part, y. A next step includes (106) setting a soft-decision metric for each bit in the symbol using the predetermined function from the determining step (102).

The invention provides a phase noise compensation method suitable for large line width and high order modulation CO-OFDM system. The method comprises the following steps: performing channel equalization on training symbol data of a receiving terminal after performing Kalman filter on the same in the frequency domain; setting pilot frequency subcarrier data with certain intervals for each OFDM symbol on a transmitting terminal, and performing preset CPE phase noise estimation and compensation at pilot frequency subcarriers in the frequency domain based on extended Kalman filter (EKF); and finally, converting frequency domain data subjected to CPE phase noise compensation into the time domain, and realizing blind ICI phase noise compensation by using the Avg-BL method, then performing pre- judgment, converting the frequency domain data subjected to the judgment into the time domain, applying time domain data and original time domain data of the receiving terminal to time domain unscented Kalman filter, calculating a final phase noise compensation value, and performing compensation. By adoption of the phase noise compensation method, a better phase noise equalization effect is obtained, and the spectrum utilization rate of the system is improved.

Systems and methods for precision phase noise measurements of radio frequency (RF) oscillators are provided. An RF signal under test can be modulated on a continuous wave (cw) laser carrier frequency via generation of modulation sidebands using an appropriate modulator. A photonic delay line can be implemented as a self-heterodyne detection system for the phase noise, allowing for photonic down-conversion of the phase noise measurement to direct current (DC). The self-heterodyne detection system allows detection outside of any 1/f noise issues. Ultra-low phase noise detection for RF frequencies in a range from below 1 GHz to beyond 100 GHz is enabled with a low noise floor in the whole frequency range. Higher-order modulation sidebands can further reduce the noise floor of the system. Ultra-low noise RF (microwave) output can be generated. The RF signal under test can be generated by a dielectric resonance oscillator or opto-electronic oscillator.

The invention discloses an adaptive spatial modulation method. For the problem of weaker anti-interference capacity of the conventional multiple-input multiple-output (MIMO) system based on spatial modulation, the method comprises the following steps of: taking differences among channels corresponding to each transmitting antenna into full consideration, adjusting a mapping mode of transmitting data according to the state of the channels, namely selecting an optimized adaptive transmission scheme which adapts to the current channel, wherein each MIMO transmitting antenna adopts different modulation modes, namely properly selecting orders of modulation according to the state of the current channel; adopting a high-order modulation scheme when the channel of the transmitting antenna is better; and adopting a low-order modulation scheme when the channel of the transmitting antenna is worse. By adoption of the modulation method provided by the invention, influence on fading of transmitting-receiving channels can be prevented effectively, and the error rate of data transmission is reduced.

A method and apparatus is disclosed to map a sequence of data to Quadrature Amplitude Modulation (QAM) constellation symbols. The method and apparatus encodes only a portion of the sequence of data and leaves a remaining portion of the sequence of data unencoded. The encoded portion of the sequence of data and the remaining unencoded portion of the sequence of data are then mapped into modulation symbols of the QAM constellation. The encoded portion of the sequence of data selects subsets of the QAM constellation, and the remaining unencoded portion of the sequence of data determines a specific modulation symbol within each subset of the QAM constellation.