Abstract: A radio communication system that uses multiple antennas to transmit signals to a plurality of mobile terminals, and that measures the reception quality of each signal that is transmitted from each antenna on a transmitting side and received by the mobile terminal, determines a main antenna based on that reception quality for real-time communication, calculates multi-dimension correlation between the main antenna and other antennas, selects resources where the multi-dimension correlation is lower than a set value, feeds back data to the transmitting side indicating the main antenna, low correlation resources and reception qualities, designates antennas having resources of low correlation as diversity antennas, and performs diversity transmission from the transmitting side of signals to the mobile station using those diversity antennas and the main antenna.

Abstract: The invention relates to methods for transmitting and receiving a data bit stream in a communication system using 16-QAM constellations. Further, an apparatus for performing the methods is provided. To improve the bit-error rate performance of the communication using the 16-QAM constellations the invention suggests the use 16-QAM constellations with specially selected mapping rules together with a special constellation rearrangement for creating different versions of the 16-QAM constellations. Further, the data stream is transmitted according to a diversity scheme employing different versions of the 16-QAM constellations obtained adhering the mapping rules and rearrangement rules defined by the invention.

Abstract: A shift space-time encoding scheme applies STBC over hierarchical modulation. A low-priority bit stream is modulated to complex symbols using STBC encoding and a high-priority bit stream is modulated to complex symbols without STBC encoding. Complex symbols from the low-priority bit stream together with the complex symbols from the high-priority bit stream are added to form a hierarchical 64-QAM constellation.

Abstract: A device of dynamic communication of information allows, on the average, non-integer bits per symbol transmission, using a compact code set or a partial response decoding receiver. A stream of selectable predetermined integer bits, e.g., k or k+1 data bits, is grouped into a selectable integer number of bit vectors which then are mapped onto corresponding signal constellations forming transmission symbols. Two or more symbols can be grouped and further encoded, so that a symbol is spread across the two or more symbols being communicated. Sequence estimation using, for example, maximum likelihood techniques, as informed by noise estimates relative to the received signal. Each branch metric in computing the path metric of a considered sequence at the receiver is weighted by the inverse of the noise power. It is desirable that the constellation selection, sequence estimation and noise estimation be performed continuously and dynamically.

Abstract: A DHT-based OFDM transmitter and receiver use discrete Hartley transform to implement multicarrier transmission. A transmission terminal (or a receiving terminal) of a transmitter and receiver comprises two IDHT (or DHT) processors and a diagonal processing device. The two IDHT processors make the DHT-OFDM system transmit the 2D modulation signal to increase the bandwidth efficiency. The diagonal processing device is used to diagonalize the circulant channel matrix into discrete memoryless subchannels, and thus only one-tap frequency domain equalizer can compensate the channel effects. Besides, the proposed DHT-OFDM transmitter and receiver are also compatible with a conventional DFT-OFDM system, and they can flexibly works with the conventional DFT-OFDM transmitter and receiver.

Abstract: Certain aspects of a method and system for independent in-phase (I) and quadrature (Q) loop amplitude control for quadrature generators may include determining an amplitude voltage associated with an in-phase (I) component and a quadrature (Q) component of a generated signal. A DC reference voltage associated with the I component and the Q component may be determined. The determined amplitude voltage may be compared with the determined reference voltage to generate a control signal. The amplitude mismatch between the I component and the Q component may be compensated by controlling a biasing current of one or more programmable buffers associated with one or both of the I component and the Q component, based on the generated control signal.

Abstract: A balanced transmitter up-converts I and Q baseband signals 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 I and Q baseband signals 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 I and Q baseband signals. 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 technique for controlling a transmitter apparatus is useful for reducing power consumption, and may be particularly applicable to portable apparatuses such as mobile transceivers which employ a battery power supply. According to an exemplary embodiment, the transmitter apparatus includes a power amplifier for amplifying a transmission signal. A processor controls the power amplifier based on a type of digital modulation associated with the transmission signal.

Abstract: The method is for managing the operation of a wireless communication device including several different communication modules respectively adapted to operate according to several given communication protocols including a UWB module operating according to a UWB protocol based on an OFDM modulation scheme. The method includes controlling the UWB module for scanning a chosen frequency band, and managing a communication to be performed by the device on the basis of the scanning result.

Abstract: A multiband OFDM_UWB transmitting and receiving apparatus is provided in Low-IF configuration to solve problems attributed to a direct-conversion transmitting and receiving apparatus. A Low-IF receiver performs sorting by rotating a sub-carrier after FFT to eliminate the need for frequency conversion using a second local signal and uses the same AD conversion clock as that for a direct conversion receiver. An FFT-free preamble can be detected by using a sequence resulting from previously multiplying an original preamble pattern and an IF frequency together.

Abstract: An apparatus and method are described for compensating for frequency and phase variations of electronic components by processing packet delay values. In one embodiment, a packet delay determination module determines packet delay values based on time values associated with a first and a second electronic component. A packet delay selection module selects a subset of the packet delay values based on the maximum frequency drift of the first electronic component. A statistical parameter determination module evaluates a first and a second parameter based on portions of the subset of packet delay values A validation module validates the parameters when each portion the subset of packet delay values includes a minimum of at least two packet delay values. An adjustment module compensates for at least one of a frequency variation and a phase variation of the first electronic component based on the parameters if the parameters are both validated.

Abstract: The present invention discloses a data transmission device and method thereof, and a data reception device and method thereof. The data transmission method in the present invention includes the following steps: encoding information data to obtain mother codes; generating transmission data including the mother codes and repetition codes from the mother codes, wherein parts of the mother codes with low reliability are selected to be repetition codes according to the modulation type of the mother codes; modulating the transmission data; transmitting the modulated data.

Abstract: There is provided a wide-band direct conversion transmitting apparatus including: a local oscillation unit generating first, second, and third oscillation signal pairs each including a pair of signals having a phase difference of 90°; an image rejection mixer unit mixing baseband transmission signals including an I signal and a Q signal having a phase difference of 90° with the first oscillation signal pair; a harmonic rejection mixer unit mixing each of the first, second, and third oscillation signal pairs with the baseband transmission signals; and an output signal selecting unit selecting output signals from the image rejection mixer unit or from the harmonic rejection mixer unit.

Abstract: Transmitter(s) (34), radio base station nodes (38) comprising transmitter(s), and methods of operating transmitter(s)/radio base station(s) involve handling discontinuous transmission indication bits, particularly when transmitting using a 16 QAM signal point constellation having an I-branch and a Q-branch (for a quadruple of bits comprising two I-branch bits, i1 and i2, and two Q-branch bits q1 and q2). The transmitter(s) (34) and the radio base station nodes (28) comprised thereof are operated to perform a Multimedia Broadcast Multicast Service over Single Frequency Network (MBSFN) transmission wherein the MBSFN transmission comprises mapping data to a Secondary Common Control Physical Channel (S-CCPCH). For the Secondary Common Control Physical Channel (S-CCPCH) the methods include operating a 16 Quadrature Amplitude Modulation (QAM) transmitter (34) according to a predetermined strategy.

Abstract: A radio transceiver device includes circuitry for radiating electromagnetic signals at a very high radio frequency both through space, as well as through wave guides that are formed within a substrate material. In one embodiment, the substrate comprises a dielectric substrate formed within a board, for example, a printed circuit board. In another embodiment of the invention, the wave guide is formed within a die of an integrated circuit radio transceiver. A plurality of transceivers with different functionality is defined. Substrate transceivers are operable to transmit through the wave guides, while local transceivers are operable to produce very short range wireless transmissions through space. A third and final transceiver is a typical wireless transceiver for communication with remote (non-local to the device) transceivers. Additionally, a multi-mode transceiver is operable to configure transmit and receive circuitry based upon transmission path.

Abstract: A method of transmitting data in a wireless communication system from a transmitter to a receiver, comprising the steps of modulating data at the transmitter using a first signal constellation pattern to obtain a first data symbol. The first data symbol is transmitted to the receiver using a first diversity branch. Further, the data is modulated at the transmitter using a second signal constellation pattern to obtain a second data symbol. Then, the second data symbol is transmitted to the receiver over a second diversity path. Finally, the received first and second data symbol are diversity combined at the receiver. The invention further relates to a transmitter and a receiver embodied to carry out the method of the invention.

Abstract: A transmitting apparatus includes a modulation signal generating section that generates a modulation signal by modulating transmission data using one of a plurality of modulation schemes. The plurality of modulation schemes include a first modulation scheme, a second modulation scheme, and a third modulation scheme, where the first modulation scheme has maximum m-ary modulation value, the second modulation scheme has a lower m-ary modulation value than the first modulation scheme, and the third modulation scheme has a lower m-ary modulation value than the second modulation scheme. The transmitting apparatus also includes a pilot signal generating section that generates a pilot signal having one of a plurality of amplitudes, the pilot signal having a lower amplitude than a maximum amplitude of the first modulation scheme.

Abstract: A method is disclosed for digital data transmission using higher order modulation schemes, wherein a plurality of bits is mapped to bit positions of a symbol and the transmission has different error probabilities for at least two out of said bit positions. A data bit is mapped to a bit position in a first modulation scheme and transmitted in a symbol on the mapped bit position of the first modulation scheme. When a request is received from a receiver, for re-transmission of a data block containing this data bit, a decision is made about a re-transmission of said bit, based on a reliability of the bit position in the first transmission, and if it is decided to retransmit the bit, the data bit is mapped to a bit position of a second modulation scheme and retransmitted in a symbol on the mapped bit position of the second modulation scheme.

Abstract: A translation transceiver device consistent with certain embodiments has a 60 GHz band receiver for receiving SD type device compatible transmissions. A demodulator demodulates the SD type transmissions. A decoder decodes the demodulated SD type transmissions into received data. An AD type encoder encodes the received data to produce AD type transmitter compatible data. An AD type modulator modulates the AD type transmitter compatible data, and an AD type 60 GHz band transmitter transmits the modulated AD type transmitter compatible data. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: Compact pulse shape partial response (CPS PR) signaling is developed for trellis based signals like QM-MSK, and for PAM/QAM type signals to improve the performance to bandwidth tradeoff. Compact pulse shaped signals are partial response signals that employ a very short pulse shaping filter and use Viterbi decoding to optimally detect the CPS signal in presence of its inherent inter-symbol interference. The CPS filters considered herein have much shorter impulse response than the well-known raised cosine (RC) filter. There is no need to equalize the received signal to eliminate ISI or to allow a fixed amount of ISI between received signal samples as sampled at the symbol rate as is common in partial response maximum likelihood (PRML) systems. Numerical results indicate that CPS QM-MSK and CPS QAM provides between several dB of gain, depending on constellation size, over PR-CPM and RC QAM, when compared at a given value of bandwidth, i.e., B99Tb.

Abstract: Methods and apparatus for reconstructing discrete-time amplitude modulation signals in polar modulation transmitters. An exemplary polar modulation transmitter includes a symbol generator, a rectangular-to-polar converter, a peak phase detector, and an amplitude modulation reconstruction circuit. The symbol generator generates rectangular-coordinate modulation symbols from which the rectangular-to-polar converter generates an amplitude modulation signal containing discrete-time amplitude samples and an angle modulation signal containing discrete-time angle samples. The peak phase detector circuit detects phase reversals or near phase reversals represented in samples of the angle modulation signal. The amplitude modulation reconstruction circuit responds by reconstructing samples in the amplitude modulation signal that correspond to detected phase reversals or a near phase reversals represented in samples of the angle modulation signal.

Abstract: A transmitter using quadrature modulation includes a rectangular to polar converter for converting data symbols into a polar form, where each polar symbol has a magnitude signal and an angle signal. Digital phase modulation circuitry includes an all digital PLL circuit for generating a phase modulated RF carrier signal responsive to the angle signal frequency control word (FCW) and a carrier frequency FCW. A digitally controlled amplifier for amplifying the phase modulated signal is controlled by a digital amplitude control circuitry for controlling the gain of the digitally controlled amplifier responsive to the magnitude signal.

Abstract: A method and apparatus for communicating wirelessly comprising creating a plurality of sub-carrier signals by quadrature amplitude modulating data onto a plurality of sub-carrier frequencies spaced apart by a sub-carrier frequency spacing interval, frequency shifting the sub-carrier signals by one half of the sub-carrier frequency spacing interval, and modulating the sub-carrier signals onto a radio frequency carrier wave for wireless transmission.

Abstract: Methods and apparatus for determining the starting points of redundancy version transmissions in a circular rate matching operation. At least one block of information bits to be transmitted are encoded to generate a plurality of coded bits, which are then segmented into a plurality of sub-blocks of coded bits. Each of the sub-blocks of coded bits is interleaved by using a certain interleaver. The interleaved coded bits of the plurality of sub-blocks are collected and filled into a circular buffer having a plurality of redundancy versions in the circular buffer, with each redundancy version corresponding to a starting bit index in the circular buffer. For each transmission, a subset of bits are selected from the circular buffer by selecting a redundancy version from among the plurality of redundancy version. The selected subset of bits are modulated by using a certain modulation scheme, and are transmitted via at least one antenna.

Abstract: Provided are a digital IF wireless transmitter, an RF modulator, and an RF modulating method.

Abstract: A method of transmitting data in a multi-carrier communication system is disclosed. More specifically, the method includes mapping at least one data symbol to at least one subcarrier of a first frequency domain and at least one data symbol to at least one subcarrier of a second frequency domain, wherein the first frequency domain and the second frequency domain are mutually exclusive and the at least one data symbol mapped to the at least one subcarrier of the second frequency domain is multiplied by a spreading code, transforming the at least one data symbol mapped to the first frequency domain and the at least one data symbol mapped to the second frequency domain by an inverse discrete Fourier transform (IDFT) module, and transmitting the transformed data symbols to a receiving end.

Abstract: Various techniques involving polar modulation are disclosed. For instance, an apparatus may include a storage medium and a calibration module. The storage medium stores multiple adjustment settings. Each of these adjustment settings corresponds to an operating condition. The calibration module selects one of the stored adjustment settings that corresponds to a current operating condition. With the selected adjustment setting, the calibration module reduces a polar modulation timing misalignment. The current operating condition may include one or more operational parameter values. Examples of such parameter values include output power level, signal frequency, and/or temperature.

Abstract: Embodiments of a digital up-converter and an N-channel modulator are provided herein. The embodiments of the digital up-converter, in combination with the N-channel modulator, are capable of efficiently filling the spectrum of one or more RF signals with one or more types of information signals. For example, the digital up-converter can fill the spectrum of one or more RF signals with both broadcast and narrowcast video and data signals. In addition, the digital up-converter is capable of flexibly mapping the information signals to one or more channels of the one or more RF signals using a novel, three-level switching architecture.

Abstract: A radio transmission device includes a modulation unit that maps a transmission bit sequence to a symbol corresponding to any one signal point by using a constellation in which a plurality of congruent equilateral triangles having a signal point as an apex are formed in each of four quadrants of an IQ plane representing an in-phase component and a quadrature component of a signal, two arbitrary neighboring equilateral triangles share one side, and signal points closest to an original point in the four quadrants form two neighboring equilateral triangles that share one side. The radio transmission device also includes a transmission unit that transmits the symbol obtained by mapping performed by the modulation unit.

Abstract: A method of dynamic tone grouping (DTG) used by a transmitter in a wireless OFDM system is proposed. First, a sequence of coded and interleaved bits is de-multiplexed into a number of bit-streams. Each bit-stream is mapped into a sequence of QAM symbols, which are grouped into non-overlapping sets of QAM symbols. Unitary transformation is then applied on the QAM symbols to produce groups of complex signals. Finally, the complex signals are dynamically mapped to subcarrier groups based on tone mapping information to improve link performance. The tone mapping information is derived from information associated with each OFDM subcarrier, such as channel state information (CSI). The OFDM subcarriers are grouped into subcarrier groups according to the tone mapping information such that the channel quality of each subcarrier group is balanced. In addition, the tone mapping information is efficiently encoded and transmitted to/from a corresponding receiver.

Abstract: To provide a receiving apparatus which is capable of demodulating information data from a multi-level modulated signal, which is generated by using a Y-00 protocol, without using high-performance component parts. In the receiving apparatus, the soft decision section 211 performs soft decision on the multi-level signal 22, in which a fixed decision level is used. A converted data identification section 214 performs logical decision on a value of the converted information data 25 in accordance with a highest-order bit of a multi-level code sequence 23 and a decision result 24 of the soft decision. A data reproduction section 215 performs an XOR operation between the converted information data 25 and a lowest-order bit of the multi-level code sequence 23, and outputs a resultant thereof as information data 23.

Abstract: A method of transmitting data including 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, to be closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data. With regard to first bit positions of the predetermined bits, the first bit positions being distinguished from second bit positions based on an error tolerance resulting from a correspondence to a signal point on a phase plane. Wherein a sum of a number of the predetermined bits included in the first data block and the predetermined bits included in the second data block is less than a total number of the first bit positions. Also including performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: The present invention provides a communication apparatus (RFIC) capable of performing a DC offset correction of an orthogonal modulation unit with a degree of accuracy higher than conventional. The orthogonal modulation unit of the RFIC includes first and second mixers, an adder and first and second switches. The first mixer receives a first local oscillation signal therein through the first switch. The second mixer receives a second local oscillation signal therein through the second switch. During calibration, a DC offset of the first mixer is adjusted in a state in which the first switch is brought to an ON state and the second switch is brought to an OFF state. Further, a DC offset of the second mixer is adjusted in a state in which the first switch is brought to an OFF state and the second switch is brought to an ON state.

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: A method and apparatus are provided for coding an OFDM/OQAM-type multi-carrier signal formed by a temporal succession of symbols comprising a set of data elements. Each of the data elements modulates a carrier frequency of the signal. Each of the data elements is formed by adding two real values in quadrature, which each correspond to a binary word of a source signal, which is modulated using a pre-determined modulation constellation, such as to transmit information over a real channel and an imaginary channel of the OFDM/OQAM symbols.

Abstract: N (integer equal to or above 3) quaternary phase shift keying (QPSK) outputs having different amplitude levels, i.e., r2=r1×2?(i?1), i=2 . . . N with respect to a maximum amplitude level r1 are superposed after power amplification to form M(=22N)-valued/quadrature amplitude modulation (QAM), and N-1 outputs si except the quaternary phase shift keying QPSK-1 having the maximum amplitude r1 are subjected to power amplification in this formation, then the outputs are combined by a directional coupler to obtain a combined signal, and an output of the quaternary phase shift keying QPSK-1 and the combined signal are transmitted from two systems of antennas to be vectorially superposed and combined in a space.

Abstract: The invention relates to method and apparatus for generating modulation symbols according to a second symbol mapping scheme by a symbol mapping unit being adapted to generate symbols according to a first symbol mapping scheme, wherein the first and second symbol mapping schemes define different mappings of data words of a stream to modulation symbols of a modulation scheme according to the respective symbol mapping scheme. Further, the invention relates to a method and apparatus for generating a mapping of data words to modulation symbols of a square 16 QAM constellation, the modulation symbols being representable by an inphase component and quadrature component. One aspect of the invention is the introduction of a bit sequence transformer unit transforming the data words to be mapped to modulation symbols prior to mapping thereby changing the Hamming distance properties of the mapping. Another aspect of the invention is the generation of a new AICO (Antipodal Inverted COnstellation) mapping scheme.

Abstract: Transmit diversity system in which constellation rearrangement is used. Both diversity signals contain the same data and both are 16-QAM, but the location of the data bits within the constellation is different. This averages the effect of the different levels of reliability of the different constellation points. A method for modifying a quadruple of data bits in a data transmission system using Quadrature. Amplitude Modulation with 16 different modulation states, 16-QAM, using an Antipodal Inverted Constellation AICO) mapping, swapping bits selecting contiguous symbol regions with bits selecting non-contiguous symbol regions. Depending on the particular pre-defined mapping and on the particular permutation of bits, inversion of selected bits may be performed in addition. The quadruples thus obtained are mapped to modulation symbols according to a pre-defined AICO mapping.

Abstract: An apparatus and method for supporting distortionless vector perturbation in a Multi-Input Multi-Output (MIMO) system are provided. The apparatus includes a transmitter for supporting distortionless vector perturbation in a MIMO system. The transmitter includes a label inserter for generating a label and for inserting the label into a user information bit, a scrambler for scrambling the user information bit inserted with the label and for generating N independent candidate sequences, a modulator for modulating the N independent candidate sequences according to a modulation scheme and a vector perturbation unit for adding a limited offset vector so that the modulated symbols are mapped to a constellation point in a feasible region. The apparatus and method provide vector perturbation with improved performance and reduced computational complexity.

Abstract: Systems and methods for dual-carrier modulation (DCM) encoding and decoding for communication systems. Some embodiments comprise a DCM encoder for applying a pre-transmission function to at least one 16-QAM input symbol and mapping resulting transformed symbols onto at least one larger constellation prior to transmission. Some embodiments joint decode, by a DCM decoder, a predetermined number of received data elements and compute a set of log-likelihood ratio (LLR) values for at least eight bits from a resulting at least one transformed symbol.

Abstract: A radio communication apparatus that is capable of switching modulation schemes. The radio communication apparatus includes a QPSK modulation signal generator, a QAM modulation signal generator, a transmission radio, and a common transmission power amplifier. The QPSK modulation signal generator modulates transmission data by a QPSK modulation scheme and outputs a QPSK modulation signal. The QAM modulation signal generator modulates transmission data by a QAM scheme and outputs a QAM modulation signal. The transmission radio receives the QPSK modulation signal or the QAM modulation signal and outputs a transmission signal, which is amplified by the common transmission power amplifier.

Abstract: An apparatus and a method for a I-Q quadrature modulation transmitter monitor a phase bias between an I branch and a Q branch of the I-Q quadrature modulation transmitter. The I-Q quadrature modulation transmitter includes the I-branch, the Q-branch equipped with a phase bias, and a tap. The apparatus is installed between the tap and the phase bias, and monitors the phase between the I branch and the Q branch which phase is introduced by the phase bias. The apparatus includes the following components: a module squarer, receiving signal from the tap and outputting a module square of the received signal; a multiplier, to multiplying data of the I-branch, data of the Q-branch and the module square to output a multiplied signal; and an averager, averaging the multiplied signal output by the multiplier. The phase between the I branch and the Q branch may be corrected according to monitoring results.

Abstract: A calibration method for reducing modulation errors in a telecommunication transmitter apparatus includes providing a plurality of pairs of test signals; the test signals of each pair are substantially in quadrature to each other, and the pairs of test signals are at least in part different with all the pairs of test signals that have a substantially equal energy. A plurality of modulated signals are generated, with each modulated signal that is generated by modulating a corresponding pair of test signals. A plurality of transformed signals are calculated, each one corresponding to the square of a corresponding modulated signal in the frequency domain. A plurality of partial error indicators are calculated, each one as a function of the modulus of a corresponding transformed signal. The partial error indicators are indicative of the modulation errors associated with the modulated signals.

Abstract: An family of improved trellis coded signaling schemes is provided that by vary the signal constellation to a smaller constellation periodically according to a pre-selected pattern. A set of specific embodiments involving periodically-reduced 4-PAM/2-PAM trellis coded schemes are disclosed that change their signal constellations periodically from 4-PAM to 2-PAM during selected intervals to improve performance. Similar periodically QAM and higher-dimensional coding schemes are also disclosed. Simplified receiver and decoder structures to decode the periodically-reduced trellis codes are also presented. The present invention allows embodiments to be produced that reduce coding complexity, reduce decoding complexity, and simplify symbol timing recovery and equalization. The cost is a moderate increase in the path memory length of the decoder.

Abstract: An RF signal, which has been obtained by a quadrature modulation, is corrected without performing quadrature demodulation. There are included an in-phase multiplier, a quadrature multiplier, an adder, a power detector, and an error determining part. The in-phase multiplier outputs an in-phase conversion signal by mixing an in-phase local signal of a predetermined local frequency with an in-phase correction user signal obtained by adding an in-phase user signal to an in-phase correction signal of a sinusoidal voltage outputted from an in-phase correction signal output unit. The quadrature multiplier outputs a quadrature conversion signal by mixing a quadrature local signal, which is different in phase by 90 degrees from the in-phase local signal, with a quadrature correction user signal obtained by adding a quadrature user signal to a quadrature correction signal, which is different in phase by 90 degrees from the in-phase correction signal, from a quadrature correction signal output unit.

Abstract: A transmitter includes an encoding module, an adaptive hierarchical signal mapping module and a transceiver module. The encoding module receives an input signal and encodes the input signal. The input signal includes data to be transmitted. The adaptive hierarchical signal mapping module modulates the encoded signal according to one or more hierarchical level distance ratios to obtain modulated symbols. The hierarchical level distance ratio defines distances between the modulated symbols. The transceiver module generates a radio frequency signal according to the modulated symbols and transmits the radio frequency signal to an air interface.

Abstract: A method for determining a bit pattern of a symbol in a wireless communication system using a cross modulation scheme. The method includes generating symbols with the cross modulation scheme, classifying positions of coding symbols by reliabilities of at least 3 classes according to an average bit error rate BER(ave) of symbols generated with the cross modulation scheme and a bit error rate BER based on transmission positions of the coding symbols in a modulation symbol during transmission of a packet with the cross modulation scheme, and determining a bit pattern such that higher-priority symbols are inserted into higher-reliability positions.

Abstract: Apparatus and methods for QAM modulation are disclosed using dual polar modulation. QAM modulation of a signal is accomplished by translating a QAM signal into two phasors having the same or constant amplitude and then phase shifting one of the phasor by 180 degrees for a differential load. The phasors are then polar modulated such that, when differentially combined in the load through summation or superposition, a QAM modulated symbol results. The use of constant amplitude phasors when power amplified for transmission of QAM modulated signals allows amplifiers to be operated in a saturation mode with greater efficiency than conventional amplifiers used in QAM modulation, which operate in a less efficient linear mode to effect amplitude modulation. Additionally, differential combining of the phasors affords relaxation of the turns of a transformer used in amplifying the phasors.

Abstract: A transmitter using quadrature modulation includes a rectangular to polar converter for converting data symbols into a polar form, where each polar symbol has a magnitude signal and an angle signal. Digital phase modulation circuitry includes an all digital PLL circuit for generating a phase modulated RF carrier signal responsive to the angle signal frequency control word (FCW) and a carrier frequency FCW. A digitally controlled amplifier for amplifying the phase modulated signal is controlled by a digital amplitude control circuitry for controlling the gain of the digitally controlled amplifier responsive to the magnitude signal.

Abstract: A calibration method and system for reducing modulation errors in a telecommunication transmitter apparatus includes providing a pair of test signals, which are substantially in quadrature to each other, and to repeat an estimation loop. The estimation loop starts with generating a modulated signal by modulating the test signals (the modulation introducing a modulation error) and continues by obtaining a squared signal corresponding to the square of the modulated signal. A transformed signal corresponding to the squared signal in the frequency domain is then calculated. The estimation loop further includes calculating an error indicator, indicative of the modulation error, according to the modulus of the transformed signal. A compensation, to be applied to the test signals for counterbalancing the modulation error, is calculated according to the error indicator and is then applied to the test signals.