Abstract: In applications where data is transmitted in frames of symbols and the transmission medium is such that the probability of correct reception of symbols is, on the average, not uniform for different symbols in a frame, transmission of test frames enables creation of information about the different probabilities of correct reception, and that information is employed by the transmitter to control the manner in which symbols are transmitted so as to ameliorate the effects of the different probabilities of correct reception.

Abstract: Methods for digital signal processing and transmission/reception systems utilizing the methods based on the use of LDPC codes, for example a LDPC code with a 3/5 code rate, in combination with a QAM modulation, for example the 16QAM or 64QAM or 256QAM modulation. In transmission, a bit permutation (Demux) is carried out prior to the QAM constellation mapping function, and in reception, the bit permutation is carried out after the QAM constellation demapping function.

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: The present invention provides methods and apparatuses for demodulation and decoding of backscattered 16-QAM RFID tag signals, represented by their in-phase and quadrature components at the output of the demodulator in the receiver portion of a reader interrogator. In a communication channel with fast changing parameters, a reader receiver adaptively and coherently corrects the in-phase and quadrature-phase components of a signal received from a tag by tracking the phase and amplitude of the signal based on a decision-feedback. A reference signal is used to correct the signal components, where the coordinates of the reference signal is updated by a tracking and an averaging algorithm. A simple implementation of the receiver in a digital signal processing environment is enabled.

Abstract: A modulation mapping method and device for Discontinuous Transmission (DTX) bits are provided. The method includes: receiving binary symbols from a downlink physical channel; replacing symbol values of DTX bits in the binary symbols with symbol values of non-DTX bits, to obtained updated binary symbols; and performing modulation mapping on the updated binary symbols. Using the DTX bits to replicate the non-DTX bits, the DTX bits are supplied to a receiving end as redundant information of the non-DTX bits, such that the performance for demodulating the non-DTX bits by the receiving end is improved. In addition, when the binary symbols on one branch are all DTX bits, modulation mapping is performed on the binary symbols on the same branch and then a real value 0 is output. That is, when the input symbols on only one branch are all DTX bits, the transmission channel for this branch may be closed down alone, and thus the system transmission power is lowered.

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: The invention relates to an improved encoding and decoding method with at least two pairs of orthogonal sequences for improving the time necessary for calculating the coefficients of the filter for the purpose of reducing the data overload in communication systems by half by means of the emission of both sequences simultaneously and the emission of the result by means of quadrature modulation to a transmission medium.

Abstract: A frequency converter converts a high frequency signal transmitted in a frequency shift keying scheme into an intermediate frequency signal having a predetermined frequency, to output the intermediate frequency signal therefrom. An amplitude limiter limits an amplitude of an output signal from the frequency converter for output. An orthogonal demodulator includes: a first signal generator which generates a pair of first local oscillation signals of which frequencies are k multiple of the predetermined frequency and of which phases are orthogonal to each other, k being an odd integer equal to or greater than 3. I-side and Q-side mixers each mix an output signal from the amplitude limiter and each of the pair of first local oscillation signals to output a mixed signal therefrom. The orthogonal demodulator generates a demodulation signal based on output signals from the I-side and Q-side mixers.

Abstract: Multicast broadcast service (MBS) transmission in a multiple-input-multiple-output (MIMO) communication being transmitted using one of three modes, a single-layer mode, a spatial multiplexing (SM) mode and a hierarchical mode. In the hierarchical mode, lower quality data is transmitted over a first MIMO layer and enhancement data is transmitted over a second MIMO layer. A receiving device may only successfully receive the lower quality data or may successfully receive the enhancement data to enhance it with. The transmission scheme used, including the mode used, may be selectable, and may be selected based on feedback.

Abstract: A data communication apparatus which improves security against eavesdropping is provided for secret communication using Y-00 protocol. In a data transmitting apparatus 101, a multi-level code generation section 111 generates, based on key information 11, a multi-level code sequence 12 in which a signal level changes so as to be approximately random numbers. A multi-level processing section 112 generates a multi-level signal 13 having a plurality of levels each corresponding to a combination between information data 10 and the multi-level code sequence 12. A level conversion section 113 divides the plurality of levels of the multi-level signal 13 into several groups, and allocates one level of a converted multi-level signal 21 to a plurality of levels included in each of the several groups in an overlapped manner. The level conversion section 113 then converts the multi-level signal 13 into the converted multi-level signal 21.

Abstract: A system and device communicates data. A modulation and mapping circuit modulates and maps data symbols into a plurality of multiple subcarriers that are orthogonal to each other based on a fixed or variable symbol rate. A frequency domain spreader circuit is operatively connected to the modulation and mapping circuit and spreads the multiple subcarriers over the frequency domain.

Abstract: A receiver used for an orthogonal frequency-division multiplexing (OFDM) system is provided. A signal processing device receives an OFDM symbol and processes the OFDM symbol according to the OFDM symbol and a carrier frequency offset compensation coefficient to generate a processed signal. The OFDM symbol includes pilots which have been hierarchically modulated and the processed signal includes the processed pilots. A signal analysis device collects the processed pilots of the processed signal and detects carrier frequency offset to generate the carrier frequency offset compensation coefficient to the signal processing device according to the processed pilots and a plurality of target decision bit error rates. A channel detection module detects a channel response of the processed signal according to the processed pilots and compensates the processed signal to generate an output data.

Abstract: A multiple output transmitter is configured for transmitting a single input data stream over two or more spatial channels using OFDM signals. The transmitter includes a commutator to select bits from the single input data stream for two or more bit streams and two or more encoders each to encode bits of one of the bit streams. The commutator operates at a bit rate and sequentially provides the selected bits of the input data stream to the encoders. A spatial bit sequencer selects groups of encoded bits from each of the encoders and assigns individual bits of a selected group at the bit-rate to block permuters in a sequential manner to distribute bits from the selected group across the block permuters. The block permuters produce interleaved blocks of bits for an associated spatial stream. The commutator assigns bits of the input bit stream to more than one encoder to allow each encoder to operate at a lower rate.

Abstract: The present invention relates in general to transferring the envelope information of a polar modulated signal to a varying pulsewidth signal, while the phase modulation is direct transferred to the phase modulation of this PWM signal. Accordingly, the resultant signal is a PWM-PPM-signal. Such a signal can efficiently amplified by use of switching amplifying stages. By the present invention four pre-distorted baseband signals are applied basically to 4 linear RF mixers and a two adders, which are, the only needed external RF building blocks to build the modulator according to the invention. That is, the basic idea of the invention resides in the way of modulation of the four baseband signals and the way of combining of the RF modulated signals.

Abstract: A method and a device for reducing the crest factor of a signal is operable to generate a correction signal as a combination of a plurality of partial correction signals having respectively predetermined frequencies and a signal having a reduced crest factor being issued as a differential between the correction signal and the signal. The respectively predetermined frequencies are selected such that the correction signal, which has a period length that is shorter than a length of the signal, is periodic. Therefore, according to the invention, only one period of the correction signal is determined and the correction signal is then determined as a periodic continuation of the one period.

Abstract: The invention provides a signal receiver. The signal receiver comprises a code removal module, a carrier removal module, a Fast Fourier Transformation (FFT) module, and a signal processor. The code removal module removes a pseudo random noise code from a first signal to obtain a second signal. The carrier removal module generates a carrier signal with a frequency of an estimated carrier frequency, generates at least one delta carrier signal with a frequency of the carrier frequency plus a delta frequency, removes the carrier signal from the second signal to obtain a third signal, and removes the delta carrier signal from the second signal to obtain a fourth signal. The FFT module derives a series of first FFT values from the third signal, and derives a series of second FFT values from the fourth signal.

Abstract: At the transmitter side, carrier waves are modulated according to an input signal for producing relevant signal points in a signal space diagram. The input signal is divided into, two, first and second, data streams. The signal points are divided into signal point groups to which data of the first data stream are assigned. Also, data of the second data stream are assigned to the signal points of each signal point group. A difference in the transmission error rate between first and second data streams is developed by shifting the signal points to other positions in the space diagram. At the receiver side, the first and/or second data streams can be reconstructed from a received signal. In TV broadcast service, a TV signal is divided by a transmitter into, low and high, frequency band components which are designated as a first and a second data stream respectively.

Abstract: Methods and receiver circuits for determining and employing decision boundary estimates for use in de-mapping QAM symbols in an OFDM receiver are disclosed. The disclosed methods efficiently use memory resources, while taking account of the frequency-selective and time-varying nature of the signal propagation. An OFDM receiver calculates a decision boundary estimate using QAM-modulated symbols selected from a group of OFDM tones and determines soft bit values for symbols selected from an adjacent tone using the decision boundary estimate. The receiver updates the decision boundary estimate using the symbols from the adjacent tone and determines soft bit values for symbols selected from a next-adjacent tone using the updated decision boundary estimate. Once the decision boundary estimate has been updated and the soft bit values have been determined for each tone, the symbol data for that tone may be discarded.

Abstract: A receiver may comprise a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component. The receiver may further comprise a digital demodulator. The digital demodulator may comprise at least one processor circuit programmed for applying a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal. Applying the phase differencer may comprise converting the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time, and converting the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time. The at least one processor circuit of the digital demodulator may also be programmed for applying a four quadrant inverse tangent to the output function to generate the information signal.

Abstract: A method (300) for performing dual carrier modulation (DCM) precoding. The method comprises generating data sub-blocks (S320), independently interleaving the sub-blocks (S330), generating bit vectors by grouping bits of the interleaved sub-blocks (S350), mapping the bit vectors into data symbols (S360), and precoding the data symbols using a precoding matrix to generate precoded symbols (S370).

Abstract: Systems and methods for generating OFDM signals are provided in which sub-carrier usage is selected and/or remapped in various manners. For example, in some embodiments remapping using a security sequence is employed; in other embodiments, decoy sub-carriers are employed; in other embodiments, mask sub-carriers are used to cover jammed portions of a channel.

Abstract: In a symbol mapping method, transmission data is encoded to generate information bits and redundancy bits. An average LLR value of bits on which the information bits are mapped is different from an average LLR value of bits on which the redundancy bits are mapped.

Abstract: The selection of at least one back-modulation element of an electromagnetic transponder from among a plurality of resistive and/or capacitive modulation elements of the load of an oscillating circuit of the transponder, including selecting the modulation element(s) according to a binary message received from a read/write terminal.

Abstract: Some embodiments discussed relate to an apparatus and method for processing signals, comprising receiving an input signal and forming a stream of digital samples of the input signal by sampling at a sampling frequency and mixing the stream of digital samples using a mixer sequence having a sine sequence and a cosine sequence based on the sampling frequency to generate an input sequence, each of the sine sequence and the cosine sequence including a plurality of components in an arrangement such that at least one of the components has a zero value and the remaining components has a non-zero value, and filtering the input sequence using a plurality of polyphase filter parts, each corresponding to the non-zero components of the sine sequence and the cosine sequence, and selectively combining the outputs of the polyphase filter parts to generate an in-phase sequence and a quadrature sequence.

Abstract: A method of demapping in a receiver including deriving M intermediate soft bit values yj for the I and Q data of the input signal as a function of the spacing in the constellation; and limiting the range of the M values yj. A look-up table index is derived for each of the limited M values yj. A look-up table, having 2N+1 entries for supporting up to N soft bit outputs, is indexed using the derived indices; and K soft bits for each of the M values yj of the I and Q data are outputted.

Abstract: Methods and apparatus to compensate for I/Q mismatch in quadrature receivers are disclosed. An example apparatus disclosed herein comprises a correction engine using first filter coefficients to compensate for I/Q mismatch present in a received quadrature signal; an adaptation engine to adapt second filter coefficients based on I/Q mismatch present in the received quadrature signal; and coefficient controller to occasionally adjust the first filter coefficients based on the second filter coefficients.

Abstract: According to an embodiment there is provided a method of modifying a symbol constellation for use in a data transmission apparatus. The method comprises receiving at a processor a starting symbol constellation suitable for use in a frequency domain parallel modulation system and defined in a complex space. The starting symbol constellation does not necessarily comprise a symbol at a zero point in the complex space. The processor is used to locate or move one of the symbols of the starting symbol constellation at the zero point of the complex space. The newly created symbol constellation may be stored in a storage medium, such as volatile or non-volatile storage, or immediately used for data transmission by mapping bits of data to the symbol constellation and by transmitting the mapped data to a receiver of a frequency domain parallel modulation system.

Abstract: A modulation/demodulation apparatus according to an embodiment of the present invention includes a sine wave generating circuit configured to output two sine waves which are orthogonal to each other and have equal amplitude, an orthogonal modulator connected to the sine wave generating circuit and configured to modulate the sine waves to generate a modulated signal, a detecting section configured to detect amplitude fluctuation in the modulated signal, a multiplying section configured to multiply the modulated signal and the amplitude fluctuation detected by the detecting section together, and an orthogonal demodulator configured to demodulate the modulated signal multiplied with the amplitude fluctuation by the multiplying section to generate a demodulated signal.

Abstract: A cellular communication system employs a plurality of bandwidths. The cellular communication system comprises a plurality of base stations (101, 103) each of which transmits a reference signal comprising a Generalised Chirp-Like, GCL, sequence. The length of the GCL sequence is dependent on the bandwidth employed by the base station (101, 103). A sequence generator (105) provides a first subset of GCL sequences for a first bandwidth selected from a set of possible GCL sequences for the first bandwidth in response to properties of a sub-sequence of GCL sequences. The sub-sequence has a length corresponding to a different bandwidth. Sequence processors (107, 109) select GCL sequences for base stations (101, 103) employing the first bandwidth from the first subset of GCL sequences. The invention exploits characteristics of GCL sequences to enable, facilitate or improve multiple bandwidth operation.

Abstract: The present invention relates to a method of transmitting a multi-carrier signal intended to be used by a system with Nt transmit antennas, where Nt is greater than or equal to two, and Nr receive antennas, where Nr is greater than or equal to one, of the type using OFDM/OQAM modulation and distributing symbols before transmission in a time-frequency plane, in which method the symbols are distributed over blocks of particular size nt.nf where nf?3 and nf?3. The method comprises real type space-time block coding by a space-time coder of blocks using a coding matrix of particular size Nt×N and of particular efficiency Nc/N to generate Nt coded sequences of N blocks of symbols of an input sequence of Nc blocks of symbols.

Abstract: A universal transmitter and a universal receiver for respectively transmitting and receiving orthogonal frequency-division multiplexing (OFDM) signals using the international television bands respectively use fixed subcarrier spacing; fixed Fast Fourier Transform (FFT)/Inverse Fast Fourier Transform (IFFT) period values; a fixed symbol duration for each cyclic prefix option; and fixed WRAN frame parameters, but a selectable channel bandwidth for transmission and reception.

Abstract: A transmitting apparatus comprising circuitry operable to generate a plurality of bit sequences using bits included in a first data block and a second data block, circuitry operable to control the plurality of bit sequences to correspond to a signal point on the phase plane, comprising a bit sequence generating unit operable to control the generation of the bit sequences to adjust an occupation rate occupied with predetermined bits included in the first data block to be closer to an occupation rate occupied with predetermined bits included in the second data block in regard to bit positions of the predetermined bits, based on an error tolerance of the respective bit sequences generated resulting from the correspondence to a signal point on the phase plane, and circuitry operable to transmit the signals obtained by multi-level modulations in accordance with each signal point.

Abstract: This disclosure relates to analog to digital conversion using irregular sampling.

Abstract: A system and method communicates and generates a Coded Orthogonal Frequency Division Multiplexed (COFDM) communications signal as a plurality of subcarriers. Selected subcarriers are turned ON and OFF while also frequency hopping and spreading the selected ON subcarriers over the frequency domain based on a fixed or variable sample rate to reduce average power for enhanced Low Probability of Interception/Low Probability of Detection (LPI/LPD) and also allow for more transmit power within a spectral mask.

Abstract: The invention enables the transmission of continuous complex numbers using a symbol based transmission scheme such as OFDM. Accordingly, complex numbers are mapped to the constellation map, enabling a fine granularity of constellation points. This scheme may be used, for example, in the transmission of video where the coefficients representing the higher frequency of each of the video components, as well as the quantization error values of the DC and near DC components, or some, possibly non-linear transformation thereof, are sent as pairs of real and imaginary portions of a complex number that comprises a symbol.

Abstract: The disclosure can provide methods and systems for autocalibrating a transceiver. The method can include upconverting a bandpass input signal by mixing the bandpass input signal with a first local oscillator signal to form an initial transmitter signal. The initial transmitter signal can be looped back to a receiver and downconverted with a second local oscillator signal having a frequency that is different from the first local oscillator to form an intermediate frequency signal. At least one of a gain and a phase of the transmitter can be adjusted based on a transmitter image sideband of the intermediate frequency signal to generate a calibrated transmitter signal having minimized transmitter image sideband.

Abstract: Hierarchical modulation preferably uses a 16-ary quadrature amplitude modulation (QAM) modulator with a convolutional encoder that combine to effectively provide unequal protection to two different segments of streaming input data, with improved power efficiency with the same bandwidth efficiency, by encoding the first segment as coded data as LSBs as the second segment remains uncoded as uncoded MSBs, with the MSBs used for QAM constellation modest reliability interquadrant demodulation and detection, and with the LSBs used for low reliability intraquadrant detection, but with the LSBs subject to convolutional encoding and decoding rendering the LSBs with high reliability detection, such that, the two segments have unequal coding and modulation for providing unequal levels of reliability detection.

Abstract: A method of feeding back channel information in an OFDM or OFDMA radio communications system is disclosed, in which a transmitting side instructs a region for measuring a downlink channel status and in which a receiving side feeds back the channel information to the transmitting side. The present invention includes the steps of transmitting instruction information instructing at least one region of at least two regions within a data frame as a signal measurement region to a receiving side and receiving the channel information estimated by a signal included in the signal measurement region instructed by the instruction information from the receiving side.

Abstract: A channel structure that can efficiently transmit more data control bits, e.g., required by future wireless communication systems, yet achieve sufficient detection and false alarm performance uses tail-biting convolutional coding and Cyclical Redundancy Check (CRC). In certain implementations, symbol repetition, interleaving and/or scrambling can also be included. Also, depending on the implementation, modulation schemes such as Bi-Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) or Quadrature Amplitude Modulation (QAM) can be used in conjunction with the other coding techniques.

Abstract: Disclosed is a digital broadcasting transmission/reception system having an improved reception performance and a signal-processing method thereof. A digital broadcasting transmitter comprises a randomizer for inputting dual TS stream consists of robust and normal packets having stuff bytes inserted in predetermined positions and randomizing the dual TS stream; a stuff byte exchanger for replacing the stuff byte of a randomized data stream from the randomizer to a predetermined known data; and an encoder for encoding a data streams to which the known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization, so that the digital broadcasting reception performance can be improved at poor multipath channels.

Abstract: In a method, modulator, transmitter and receiver, the modulator of data signals to be transmitted simultaneously to at least two receiving mobile stations in the same transmission time slot is adapted to select rotational angle of a QPSK transmission modulation, such as a hybrid ?-QPSK modulation used to modulate the data signals to the at least two mobile stations in response to the capabilities of the mobile stations that share the same transmission slot.

Abstract: In a satellite radio navigation receiver receiving a transmitted radio navigation signal, a method of removing I/Q-mismatches in the received signal, comprising: resolving the received signal into I and Q signal component, and providing them as inputs to a demixing stage which removes unwanted signals, the demixing stage including first and second cross-coupled adaptive filters, whose coefficients are updated by the outputs of the demixing stage, the outputs of the demixing stage representing an IQ mismatch corrected signal. The coefficients are updated only by the polarity values of the outputs, resulting in great simplification. The receiver may be a zero-IF or low-IF receiver, and may operate on time domain or frequency domain signals.

Abstract: A method and an arrangement for processing a received signal which comprises phase-shift modulated or amplitude-quadrature modulated part-signals which are transmitted in a plurality of different frequency bands, wherein the received signal is processed in a plurality of stages in succession, by multiplying all the input signals to each of the stages by two mutually orthogonal signals in each case to form two intermediate signals in each case, wherein the intermediate signals from one stage in each case act as the input signals to whichever is the succeeding stage in the particular case and the received signal acts as the input signal to the first stage, and wherein an in-phase and/or an quadrature component of the individual part-signals in the different frequency bands are determined from the intermediate signals from the last stage. Parallel, simultaneous reception of a plurality of frequency bands can be implemented relatively easily in this way.

Abstract: One embodiment comprises a transmitter precoder operating on an input signal to produce an output signal for modulation. The output signal is transmitted using a constellation with a constellation density. The transmitter precoder comprises scaler logic, precoder logic and selection logic. The scaler logic scales the input signal to maintain constant power on the input signal independent of the constellation density. The precoder logic precodes the scaled signal to produce a dither signal limited to a range of values. The range is inversely proportional to the constellation density. The selection logic is operable in two states. In the first state, the selection logic combines the scaled signal with the dither signal to produce the output signal. In the second state, the selection provides the scaled signal as the output signal.

Abstract: In an OFDM communication system, wherein a frequency bandwidth is divided into multiple Physical Resource Units (PRUs), a Frequency Partitioning Configuration Module (FPCM) is provided that configures a physical layer for use in multiple coverage areas. The FPCM divides the PRUs into a first group, for frequency selective allocations, and a second group, for frequency diverse allocations. The FPCM subdivides each of the two groups into multiple sets of PRUs, maps the sets of PRUs from the first group to consecutive PRUs allocated for contiguous segment allocation (CS-PRUs), and maps the sets of PRUs from the second group to consecutive PRUs allocated for distributed segment allocation (DS-PRUs). The FPCM permutes the DS-PRUs and allocates the CS-PRUs and the permuted DS-PRUs to at least one frequency partition.

Abstract: A digital television transmitter and a method of coding main and enhanced data in the digital television transmitter are disclosed. In the digital television transmitter, a byte-symbol converter converts main and enhanced data packets into symbols, wherein at least one of the enhanced data packets may include data place holders for known data symbols. A known data generator generates a known data symbol. A symbol processor processes a first symbol outputted from the byte-symbol converter. Herein, the symbol processor may post-decode a first bit of the known data symbol and output the post-decoded bit and an initialization data bit when the first symbol is a symbol representing one of the place holders. A trellis encoder has one or more memories for trellis-encoding a second symbol outputted from the symbol processor, wherein the memories are initialized when the initialization data bit is processed in the trellis encoder.

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: A fixed-point IFFT device in an OFDMA digital modulator is disclosed, which comprises a sub-carrier activity detector configured to detect a number of active sub-carriers in an OFDMA symbol set being transmitted in a given OFDMA symbol period, a scale termination calculator configured to generate an output for determining at which stage to terminate the IFFT scaling as a predetermined function of the number of active sub-carriers, a scaling controller configured to generate a plurality of control signals based on the output of the scale termination calculator, and an IFFT unit having a plurality of scaling stages each of which is controlled by one of the generated control signals.

Abstract: An improved training sequence for acquiring symbol boundary timing at a receiver of a data transmission system is disclosed. One aspect pertains to an improved training sequence wherein groups of identical symbols are transmitted by a transmitter. These symbols can be supplied to the transmitter in a time domain or a frequency domain manner. The improved training sequence facilitates symbol boundary determination at a receiver.

Abstract: Various aspects of a method for minimum mean square error soft interference cancellation (MMSE-SIC) based sub-optimal maximum likelihood (ML) detection for a multiple input multiple output (MIMO) wireless system may comprise selecting at least one constellation point in a constellation map based on at least one of a plurality of received symbols. A number of the at least one constellation point may be less than or equal to a number of previously selected constellation points in a previous constellation map. At least one of the plurality of received symbols may be decoded based on the selected at least one constellation point.