Abstract: Provided are a coefficient multiplier and digital delta-sigma modulator using the same. The coefficient multiplier has the average of output signals of respective dependent multipliers as an effective coefficient using a coefficient averaging technique without employing an adder that has a complex structure and occupies a large chip area. Accordingly, the coefficient multiplier has a simple hardware constitution and small chip area in comparison with a canonical signed digit (CSD) coefficient multiplier, and the digital delta-sigma modulator employing the coefficient multiplier has a simple structure and small size.

Abstract: A data transmitting and receiving method of transmitting supplementary data in an OFDM communication system is disclosed. The method of transmitting and receiving the OFDM signal includes: mapping an input bit stream into at least one transfer symbol; changing at least one of amplitudes and phases of the transfer symbols that are transmitted by a specific sub-carrier group having a plurality of sub-carriers using constellation modification information to indicate specific additional data; and transmitting the transfer symbols, to which the changing is carried out, to a receiving end by an orthogonal frequency division multiplexing data processing, the constellation modification information being identical to each other with respect to the transfer symbols that are transmitted by the specific sub-carrier group.

Abstract: The invention relates to methods for transmitting and receiving a data bit stream in a communication system using a 16-QAM constellation. Further, an apparatus for performing the methods is provided. To provide a modulation and coding scheme using a signal space expansion and 16-QAM which improves the bit-error rate in comparison to QPSK modulated signals and still provides the possibility to implement coders and decoders with low complexity the invention suggests the use a 16-QAM constellation with specially selected mapping rules together with repetition coding (signal space expansion) and interleaving of the data stream to be transmitted.

Abstract: A receiver with selective sign inversion which can compensate for cross-over conversion is described. Some inputs may be a differential data inputs; a sign select input; a converter having inputs coupled to the differential data inputs and having first and second outputs, wherein the converter is adapted to convert a differential data signal received at the differential data input into a digital data output at the first output and a sign signal at the second output; and a selective sign inverter having a first input coupled to the sign output of the analogue-to-digital converter, a second input coupled to the sign select input and an output, wherein the signal received at the first input of the selective sign inverter is selectively inverted in dependence on the signal received at the second input in order to provide the modified sign select signal.

Abstract: Apparatus includes an equalizer having a signal input, a control input and an output; a controllable power supply having a control input and an output, the input of the controllable power supply being coupled to the output of the equalizer; a power amplifier having a main signal input, a power supply input, and an output, the power supply input being coupled to the output of the controllable power supply; and a controller having first and second inputs and an output, the first input being coupled directly or indirectly to the output of the controllable power supply, the second input being coupled to a node upstream of the equalizer, and the output being coupled to the control input of the equalizer; the equalizer being configured to apply equalization to an envelope signal received at its input and to provide a resulting equalized envelope signal at its output, the controllable power supply being configured to provide a power signal at its output based on the equalized envelope signal received at its input, t

Abstract: A transmission of information within a wireless cellular network may include a first and second type of information. A subframe is produced that includes a plurality of symbols, wherein at least one symbol is designated as a data symbol and at least one symbol is designated as a reference signal symbol that contains a pre-defined reference signal. The first type of information is embedded in the data symbols. If the second type of data is expected, then the second type of information is embedded in at least one reference symbol by quadrature amplitude modulating the pre-defined reference signal. The subframe is then transmitted from one node in the network to a second node. In some embodiments, if it is determined that the second node is not expecting the second type of information, then a discontinuous transmission (DTX) response is embedded in the reference symbol instead of the second type of information.

Abstract: A method, an apparatus and a system for transmitting information bits are provided. The method for transmitting information bits includes: dividing the information bits to be transmitted into at least two groups; encoding the information bits to be transmitted in each group; modulating the coded bits obtained by the encoding to obtain modulation symbols, in which each modulation symbol is obtained by the modulation of the coded bits in the same group; and mapping and transmitting the modulation symbols. In this way, the receiving end easily reduces the algorithm complexity, thereby ensuring the performance of the receiving end.

Abstract: A mixed-signal adaptive integrated circuit may comprise a primary function circuit, a digitally controlled analog sub-system cooperatively connected with the primary function circuit, and an on-chip signal analyzer. The on-chip signal analyzer may be arranged to analyze RF signals. The signal analyzer may comprise at least one multiplexor for selecting selected RF signals for comparison and analysis, and may comprise a digital signal processor (DSP) for analyzing the selected RF signals and adjusting at least one operational parameter of the digitally controlled analog sub-system responsive to the analysis.

Abstract: A configurable transceiver includes an RF receiver section that generates at least one downconverted signal from a received RF signal. A receiver processing module processes at least one downconverted signal in a plurality of receiver stages to produce a stream of inbound data, wherein the receiver processing module is configurable in response to a control signal to selectively bypass at least one of the plurality of receiver processing stages. A transmitter processing module processes outbound data in a plurality of transmitter stages to produce at least one baseband signal, wherein the receiver processing module is configurable in response to the control signal to selectively bypass at least one of the plurality of transmitter processing stages. An RF transmitter section generates at least one RF signal from the at least one baseband signal.

Abstract: A wireless communication unit includes a frequency generation circuit, and a linearised transmitter operably coupled to the frequency generation circuit and having a forward path for routing a signal to be transmitted; and a feedback path, operably coupled to a power amplifier and the forward path for feeding back a portion of the signal to be transmitted. The feedback path and forward path form two loops in quadrature. The frequency generation circuit includes independent phase shift elements arranged to independently phase shift the two loops in quadrature (‘I’ and ‘Q’).

Abstract: Aspects of a method and system for enhancing efficiency by modulating power amplifier (PA) gain are presented. Aspects of the system may comprise a PA gain modulator that enables modification of an amplitude of a digital baseband signal. A baseband processor may enable computation of a first gain value based on the modification. The baseband processor may enable computation of a second gain value based on the first gain value. A PA may enable generation of an RF output signal based on the modified digital baseband signal and the second gain value.

Abstract: A method for performing burst mapping on transmission data by a transmitter in a mobile communication system using a 16-ary Quadrature Amplitude Modulation (16-QAM) modulation scheme is disclosed. The burst mapping method includes generating control information bits and user data bits by encoding input control information and user data; dividing the control information bits and user data bits into more than two bursts; and arranging a Training Sequence Code (TSC) in a center of each burst, placing the coded control information bits in positions adjacent to the TSC, and swapping the user data bits with bits mapped to higher-reliability positions among the control information bits.

Abstract: Provided is a method for transmitting data in a communication or broadcasting system using a linear block code by generating a codeword by encoding input information data bits, interleaving the codeword; outputting modulation signal-constituting bits by bit-mapping the interleaved codeword using a bit-mapping table predetermined depending on a modulation scheme and a coding rate, outputting a modulation signal by modulating the modulation signal-constituting bits and transmitting the modulation signal via a transmit antenna.

Abstract: The present invention provides a system (400), device (200, 300), and method (200) for a spatial multiplexing (SMX) transmission scheme combined with symbol spreading and rotation using a pre-determined matrix R, which can greatly improve system performance without requiring additional bandwidth or power consumption under fast Rayleigh flat fading channels or high frequency-selective channels in UWB systems. Because of the lattice-based structure, sphere decoding is employed to reduce the complexity of ML decoding while maintaining the near ML performance. On the other hand, ZF and MMSE receivers can also be used due to the systematic structure at the transmitter.

Abstract: The digital RF transmitter includes a decoder for receiving the in phase (I) and quadrature (Q) digital baseband signals, a phase generator for generating eight waveforms at a carrier frequency where each phase is a multiple of 45 degrees, a first set of main amplifiers of fixed output power, a second set of auxiliary amplifiers of fixed output power such that the ratio of the voltage amplitudes at the outputs of the second set of auxiliary amplifiers to the voltage amplitudes at the outputs of the first set of main amplifiers is fixed at sqrt(2)?1, and a set of multiplexers for selecting one of the eight carrier waveforms, or an off signal, to transmit to each of the first set of main amplifiers and the second set of auxiliary amplifiers based on both the in phase (I) digital baseband signal and the quadrature (Q) digital baseband signal.

Abstract: A transmission method for multi-antenna retransmission is provided, comprising steps of: generating the bits to be transmitted by respective antennas; mapping the bits to be transmitted by the respective antennas into symbols; and multiplying by a constant the vector constituted by the mapped symbols transmitted by multiple antennas, wherein the resulting vector is orthogonal to the matrix constituted by the symbols previously transmitted by multiple antennas, and transmitting the orthogonal symbols. According to the method of the present invention, the remapped symbols transmitted by the respective antennas and the symbols previously transmitted by the respective antennas constitute a matrix that has an orthogonal property. The orthogonal property can be used to effectively detect signals. In addition, the method has a reception algorithm with low complexity and brings about significant performance gains over conventional methods.

Abstract: A multi-channel encoder, demodulator, modulator and transmission system for digital video insertion in network edge applications includes a circuit comprising slots for receiving a plurality of plug-in demodulator and encoder cards, a transmission stream multiplexer in communication with the slots, a QAM modulator in communication with the transmission stream modulator, a optical transmission section in communication with the QAM modulator, and a monitor and control system for monitoring and controlling the circuit. The system also includes a power supply for powering the circuit, and a lockable cabinet for enclosing the circuit, the plug-in demodulator and encoder cards, and the power supply, the lockable cabinet enclosing space for a cable modem connectable to the circuit.

Abstract: A method for deriving a bound on communications capacity with ideal quadrature layered communications QLM and a set of demodulation algorithms for QLM. Communications links using QLM can approximate this bound and support higher data rates than allowed by the Shannon bound. Demodulation algorithms can be grouped into symbol algorithms and bit algorithms. Bit algorithms support higher data rates than symbol algorithms with lower computational complexities at the expense of demodulation loss which can be reduced with bit correlation error correction decoding which is orthogonal to the channel error correction decoding. Representative symbol and bit implementation algorithms are derived. Modulation performance is compared with phase-shift-keying PSK and quadrature amplitude modulation QAM.

Abstract: Symbol detection and soft dempapping methods and systems are provided. Individual subset symbol detection according to an embodiment of the invention involves identifying a search subset of a transmission symbol set for a transmission symbol. For each other transmission symbol in communication signals, multiple search subsets of the transmission symbol set are identified. The multiple search subsets include respective search subsets based on each transmission symbol in either the search subset for the first identified one of the transmission symbols or each of the multiple search subsets identified for a different one of the other transmission symbols. Symbol detection errors may be detected by identifying competing symbols and computing competing distances. Soft demapping may be provided by calculating soft decision results based on detected symbols and weighting the soft decision result.

Abstract: The present invention employs hierarchical modulation to simultaneously transmit information on different modulation layers using a carrier RF signal. Initially, first data to be transmitted is assigned to a first modulation layer and second data is assigned to a second modulation layer. In one embodiment of the present invention, the first and second data are assigned based on reliability criteria. The first and second modulation layers are hierarchical modulation layers of the carrier RF signal. Once assigned, the first data is transmitted using the first modulation layer of the carrier RF signal and the second data is transmitted using the second modulation layer of the carrier RF signal. In one embodiment of the present invention, information may be transmitted to one end user using one modulation layer, and information may be transmitted to a different end user using a different modulation layer.

Abstract: An apparatus and a method for operating a transmitter supporting constellation rearrangement for 256-Quadrature Amplitude Modulation (QAM) in a broadband wireless access system are provided. The method include generating complex symbols according to a first version of a constellation mapping rule, transmitting an initial transmit packet comprising the complex symbols, and when retransmitting the initial transmit packet, generating complex symbols according to a second first version of a constellation mapping rule.

Abstract: An arrangement and method for channel mapping in a UTRA TDD HSDPA wireless communication system by applying interleaving functions in first (530) and second (540) interleaving means to a bit sequence to produce symbols for mapping to physical channels, the first and second interleaving means being arranged to map symbols from respectively systematic and parity bits in a predetermined scheme, e.g., mapping symbols in a forward direction when a channel has an even index number, and in a reverse direction when a channel has an odd index number. The symbols may comprise bit-pairs, each of a systematic bit and parity bit. Systematic bits are preferably mapped to high reliability bit positions in TDD HSDPA, achieving a performance gain of between 0.2 dB and 0.5 dB. The forwards/reverse mapping allows a degree of interleaving that improves system performance in fading channels or channels disturbed by short time period noise or interference.

Abstract: The present invention provides a constellation mapping method, and the method includes: flipping a plurality of bits in each modulation symbol unit to be mapped in part of or all of modulation symbol units to be mapped of a bit sequence to be mapped; and mapping each flipped modulation symbol unit to be mapped as a modulation symbol in a constellation. By means of the present invention, the phenomenon that consecutive bits have the same reliability can be effectively avoided by changing unevenness of reliability distribution of the consecutive bits, and at the same time, the link performance can be improved.

Abstract: A vestigial sideband (VSB) modulation apparatus includes a signal processing unit which extracts an I-axis data signal component and a Q-axis data signal component from a baseband signal with symbol data superimposed thereon, a band-limiting filter which frequency-shifts the I-axis data signal component and the Q-axis data signal component, extracted by the signal processing unit, by only a specific frequency smaller than a rate of the symbol data and limits a passband width by a frequency width smaller than the rate of the symbol data, and a quadrature modulating unit which obtains a VSB modulation signal by quadrature-modulating the I-axis data signal component and the Q-axis data signal component output from the band-limiting filter.

Abstract: Various wireless precoding systems and methods are presented. In some embodiments, a wireless transmitter comprises an antenna precoding block, a transform block, and multiple transmit antennas. The antenna precoding block receives frequency coefficients from multiple data streams and distributes the frequency coefficients across multiple transmit signals in accordance with frequency-dependent matrices. The transform block transforms the precoded frequency coefficients into multiple time domain transmit signals to be transmitted by the multiple antennas. The frequency coefficients from multiple data streams may be partitioned into tone groups, and all the frequency coefficients from a given tone group may be redistributed in accordance with a single matrix for that tone group. In some implementations, the frequency coefficients within a tone group for a given data stream may also be precoded. In some alternative embodiments, tone group precoding may be employed in a single channel system.

Abstract: A modulation system can switch between two modulation modes. In order to comply with limits on peak power in spectral bands outside the RF operating one the transmitter is required to ramp down to a condition of minimal power. To avoid fixed ramping and trailing bits, the transmitting signal is subjected to FIR filtering. The two FIR filters are primed with a sequence using a parallel input mode before serially entering the information data.

Abstract: A method of transmitting a control channel format indicator (CCFI), also known as PCFICH (Physical Control Format Indicator Channel), in case where the length of a coded CCFI is not an integer multiple of three, including mapping a plurality of two-bit CCFI into a codebook with each component codeword having three bits; generating a sequence of codewords selected from the codebook by repeating the selected component codeword for predetermined times; generating a codeword by concatenating the sequence of the selected component codewords with the original CCFI bits; and transmitting the codeword carrying information of CCFI. The method further includes a step of generating a permutation of each of the four codewords by assigning K repetitions of the three-bit component codeword to the number of K resource units respectively and mapping remaining K bits of each of the four codewords separately to the number of K resource units.

Abstract: A set of data symbols is selected from a set of modulation constellation, and a sample-mean of the set of data symbols is determined. Each data symbol is first shifted by the sample-mean to obtain a shifted data symbol, and then the shifted symbol is multiplied by a first constant to obtain a scaled data symbol. A second constant is added to the scaled data symbol to obtain a mapped data symbol. The sample-mean is multiplied by a third constant to obtain a sample-mean mapped symbol. The set of mapped data symbols and the sample-mean mapped symbol are then transmitted as a resource block.

Abstract: Provided is a measuring apparatus which measures a quadrature modulator, including a supplying section supplying the quadrature modulator with a reference I signal having a predetermined frequency and a reference Q signal whose phase is shifted by 90 degrees from the reference I signal, an extracting section extracting, from a modulation signal output from the quadrature modulator by applying quadrature modulation to the reference IQ signals, a main signal component as the reference IQ signals modulated, and an image signal component occurring at a position symmetric to the modulated reference IQ signals with respect to the carrier signal, and a measurement value calculating section calculating at least one of a carrier phase error and amplitude error which occur between I signal and Q signal sides of the quadrature modulator, and a skew between IQ signals of the quadrature modulator, based on the main signal component and image signal component.

Abstract: Multi-carrier transmission is performed without inserting a repetitive signal into guard interval periods. A transmitter provides guard interval periods by using a null signal to save transmission power and prevent the deterioration of the SN ratio. Delayed waves at the head of each received symbol cause high-frequency waves to occur and carriers to interfere with one another. Accordingly, a receiver adds a component following each received symbol to a delayed-wave component at the head of the received symbol. As a result, the delayed-wave component at the head of the received symbol and the added component become continuous in wave form and subcarriers do not interfere with each other.

Abstract: A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

Abstract: A communication apparatus for executing half-duplex data communication conforming to V.

Abstract: A method of transmitting data that includes controlling generation of bit sequences to adjust an occupation rate occupied with predetermined bits included in a first data block, which is obtained by encoding first data in a first encoding process, to be equal or closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data in a second encoding process, in regard to first bit positions of the bit sequences generated using bits included in the first and second data blocks; and performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: A multiple-mode modulator is configured similarly to a direct conversion quadrature modulator with an infusion of an amplitude modulation signal path from a large signal polar modulator to improve the power amplifier efficiency. The multiple-mode modulator also includes a radio frequency signal path. The multiple-mode modulator is configured to receive a baseband signal, convert the baseband signal to a radio frequency (RF) signal, and to process the RF signal according to either a polar mode or a quadrature mode, depending on a time-varying input voltage of the RF signal. When the power amplifier operates in the linear region, the RF signal is processed according to the quadrature mode. When the power amplifier operates in the compressed region, the RF signal is processed according to the polar mode. The multiple-mode modulator can be configured according to a small signal polar architecture or a large signal polar architecture, having either an open-loop or closed-loop configuration.

Abstract: The present invention relates to a method of transmitting and receiving signals and a corresponding apparatus. One aspect of the present invention relates to a method of extracting PLP from data slices.

Abstract: A balanced transmitter up-converts a baseband signal directly from baseband-to-RF. The up-conversion process is sufficiently linear that no IF processing is required, even in communications applications that have stringent requirements on spectral growth. In operation, the balanced modulator sub-harmonically samples the baseband signal in a balanced and differential manner, resulting in harmonically rich signal. The harmonically rich signal contains multiple harmonic images that repeat at multiples of the sampling frequency, where each harmonic contains the necessary information to reconstruct the baseband signal. The differential sampling is performed according to a first and second control signals that are phase shifted with respect to each other. In embodiments of the invention, the control signals have pulse widths (or apertures) that operate to improve energy transfer to a desired harmonic in the harmonically rich signal.

Abstract: A transmitting apparatus, that includes a means for generating bit sequences to adjust an occupation rate occupied with predetermined bits included in a first data block, which is obtained by encoding first data in a first encoding process, to be equal or closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data in a second encoding process, in regard to first bit positions of the bit sequences generated using bits included in the first and second data blocks and a modulator for performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: An integrated transmit circuit includes a voltage controlled oscillator (702) for generating an input frequency signal (e.g., VCO) that is provided to a divide by two quadrature generator circuit (706) which generates therefrom in-phase and quadrature clocking signals (I, IB, Q, QB) that are applied to control a plurality of transmission gates (711-718) configured in a matched switching topology (710) so as to selectively pass pulses from the input frequency signal, thereby generating interleaved LO pulses (Ø1, Ø1B, . . . Ø4, Ø4B). By applying the interleaved LO pulses to control the transmission gates (26, 28, 30, 32, 34, 36, 38, and 40) in the upmixer (720), the +I, ?I, +Q, ?Q input signals are interleaved over a plurality of phases of a carrier period to produce differential outputs (42, 44).

Abstract: The present invention relates to a method of transmitting and a method of receiving signals and corresponding apparatus. One aspect of the present invention relates to an efficient layer 1 (L1) processing method for a transmitter and a receiver using data slices.

Abstract: A system and method that demodulates the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

Abstract: An IQ-modulator pre-distorter includes an iteratively updated digital filter (gQ0, gQ1) for filtering one of the branches of an IQ-signal to compensate for IQ-modulator generated amplitude errors. An iteratively updated digital filter (cQI0, cQI1), cross-connected from one of the branches to the other branch, filters one of the components of an IQ-signal to compensate for IQ-modulator generated inter-modulation between the branches. Iteratively updated compensators (dcI, dcQ) counteract IQ-modulator generated offset errors.

Abstract: The present invention relates to a method of transmitting and a method of receiving signals and corresponding apparatus. One aspect of the present invention relates to an efficient L1 signaling method for an efficient transmitter and an efficient receiver using the efficient L1 signaling method for an efficient cable broadcasting.

Abstract: A method for amplitude modulating a carrier signal according to one embodiment includes splitting the carrier signal into first and second paths; phase modulating the carrier signal on the first path; phase modulating the carrier signal on the second path; combining the phase modulated carrier signal on the first path with the phase modulated carrier signal on the second path for generating an amplitude modulated output signal; and wherein a first feedback loop couples the amplitude modulated output signal to circuitry for phase modulating the carrier signal on the second path but not to circuitry for phase modulating the carrier signal on the first path, the first feedback loop being for reducing a residual phase variation of the amplitude modulated output signal. Additional systems and methods are also presented.

Abstract: A modulation method and device for modulating transfer format combination indicator TFCI information, the method including: dividing equally original TFCI information in a unit of 2 bits in a transmission time interval TTI; extending the resultant respective parts of the TFCI information after the division to correspond to identifiers of one or more designated energy points in a preset constellation; and mapping the respective extended parts of the TFCI information to the corresponding energy points for modulating.

Abstract: A method and apparatus for generating a TSC in a communication system are provided, in which a pair of sequences A and B having auto-correlation and cross-correlation properties are generated and the TSC is generated by inserting guard sequences Z each having z zero symbols in the most significant bits of the sequences A and B.

Abstract: An input bit stream is phase rotated by reversing bit pairs and inverting bits. The manipulated bit stream is mapped to a symbol and the mapped symbol is converted to the time domain such that an output of the time domain conversion is an ordered set of N samples that allow efficient cyclic prefix insertion without rotation at the symbol level. A first portion of the set of samples is stored in a buffer, and the complete set of samples is output followed by the buffered first portion of the set of samples for transmission. The set of samples can be NIFFT samples of an OFDM symbol and the first portion can be NCP samples that make up the cyclic prefix CP. Re-ordering the bits can be done by swapping bit pairs and inverting one of the swapped pairs, or by trivial (1, ?1, ?j) phase rotation. The buffer is ¼ the length of prior art OFDM buffers and CP-related processing delays are significantly reduced.

Abstract: A pulse amplitude modulation (PAM) signal generator that injects a copy of a pulse into the PAM baseband signal prior to frequency upconversion and power amplification. The pulse comprises a function of, or an extra copy of, a pulse in the PAM baseband signal. The pulse injector analyzes the PAM baseband signal for times when a predetermined threshold is exceeded and forms a pulse that is constructed and arranged to reduce the amplitude of the PAM baseband signal to a desired peak amplitude when the pulse is added to the PAM baseband signal. In other embodiments the peak-to-RMS amplitude ratio reducing methods and apparatus used to process PAM signal are adapted for reducing peak-to-RMS amplitude ratios of amplitude modulation signals in polar modulation transmitters. Peak-to-RMS amplitude ratio reduction is performed in the quadrature domain, the polar domain, or both the quadrature and polar domains.

Abstract: A transmitter using pseudo-orthogonal code includes a serial-to-parallel converter for converting serial transmission data into 9-bit parallel data, and a pseudo-orthogonal code memory for receiving the parallel data from the serial-to-parallel converter and outputting 16-bit pseudo-orthogonal code by using the received data as addresses. The pseudo-orthogonal code memory has the relationship of the input address and output code, as expressed in the following equation: c(i)=0.5×((?1)b2?(i1b1)?(i0b0) (?1)b5?i2?(i1b4)?(i0b3) (?1)b8?i3?(i1b7)?(i0b6) (?1)( b2?b5?b8)?i3?i2?(i1(b1?b4?b7))?(i0(b0?b3?b6))) where C(i) is a pseudo-orthogonal code value, i is each bit of the pseudo-orthogonal code, 0?i?15, and b0-b8 are a transmission data bit stream input in the memory as addresses. Accordingly, the transmission efficiency of the transmitter/receiver using orthogonal code can be remarkably improved.

Abstract: Techniques for data transmission using high-order modulation are provided. According to one aspect, parameters of a transmission link are determined, and a multilevel coding scheme and a high-order modulation signal constellation are selected on the basis of the determined parameters. An information indicating the selected multilevel coding scheme and high-order modulation signal constellation and data symbols encoded according to the selected multilevel coding scheme and high-order modulation signal constellation are transmitted. In other aspects, QPSK data symbols are embedded between M-QAM data symbols or M-PSK data symbols with M>4. The QPSK data symbols may be used to improve the efficiency of the decoding process.

Abstract: An IQ-modulator pre-distorter includes means for pre-distorting each IQ-vector by a 2-dimensional linear transformation that depends on the value of the IQ-vector to be pre-distorted. The transformation is based on polynomials in the I- and Q-components. In a preferred embodiment the transformation is based on a 2×2 dimensional lookup table matrix, the elements (T11, T12, T21, T22) of which are sampled polynomials in the I- and Q-components of the IQ-vector.