Abstract: A method for transmitting to a UE control information comprising: channelization-code-set information (xccs,1, xccs,2, . . . , xccs,7); modulation-scheme and number of transport blocks information (xms,1, xms,2, xms,3, xms,4, xms,5); and precoding weight information (xpwipb,1, xpwipb,2, xpwipb,3, xpwipb,4). The method includes: multiplexing the channelization-code-set information, the modulation-scheme and number of transport blocks information and the precoding weight information to give a sequence of sixteen bits x1,1, x1,2, . . . , x1,16, where x1,i=xccs,i for i=1, 2, . . . , 7; x1,i=xms,i-7 for i=8, 9, 10, 11, 12; and x1,i=xpwipb,i-12 for i=13, 14, 15, 16; applying rate 1/2 convolutional coding to the sequence of bits x1,1, x1,2, . . . , x1,16 to obtain bit sequence z1,1, z1,2, . . . , z1,48; and puncturing the bits z1,1, z1,2, z1,4, z1,8, z1,42, z1,45, z1,47, z1,48 from sequence z1,1, z1,2, . . . , z1,48 to obtain an output sequence r1,1, r1,2 . . . r1,40.

Abstract: A software defined radio is disclosed. The software defined radio may utilize a method for encoding a bit stream into non-periodic spiral-based symbol waveforms for transmission and reception. The method includes transmitting a signal constructed from one or more non-periodic modulation sets residing on a memory system of the software defined radio, where each modulation set corresponds to a symbol alphabet and provides non-periodic symbol waveforms corresponding to symbol bit sequences segmented by a microprocessor according to alphabet size. The method also includes receiving the signal constructed from one or more spiral modulation sets, wherein the signal from one or more spiral modulation sets are filtered and then fed to an analog to digital converter, where the signal constructed from the one or more spiral modulation sets is digitized and are fed to the microprocessor. A non-transitory computer storage media may also execute the method.

Abstract: A receiver receives a repeating or periodic signal and, based on the signal, estimates a carrier frequency offset for the receiver. Based on the signal and the estimated carrier offset, an I/Q mismatch for the receiver is estimated and compensation for the estimated I/Q mismatch is performed. After compensating for the estimated receiver I/Q mismatch, the carrier frequency offset is re-estimated.

Abstract: A projection code is applied to encode symbols as weighted arithmetic sums of approximately random subsets of binary source bits. Pairs of the symbols are combined to form constellation points, which are sequentially mapped through a constellation to modulate a data signal.

Abstract: A receiver receives an inter-symbol correlated (ISC) signal with information symbols and a corresponding parity symbol. Values of information symbols are estimated utilizing parity samples that are generated from the parity symbols. One or more maximum likelihood (ML) decoding metrics are generated for the information symbols. One or more estimations are generated for the information symbols based on the one or more ML decoding metrics. A parity metric is generated for each of the one or more generated estimations of the information symbols. The parity metric is generated by summing a plurality of values of one of the generated estimations to generate a sum, and wrapping the sum to obtain a parity check value that is within the boundaries of a symbol constellation utilized in generating the information symbols.

Abstract: A receiver may be operable to generate estimates of transmitted symbols using a sequence estimation process that may incorporate a non-linear model. The non-linear model may be adapted by the receiver based on particular communication information that may be indicative of non-linearity experienced by the transmitted symbols. The receiver may generate a reconstructed signal from the estimates of the transmitted symbols. The receiver may adapt the non-linear model based on values of an error signal generated from the reconstructed signal, and the values of the error signal may be generated from a portion of the generated estimates that may correspond to known symbols and/or information symbols. The values of the error signal corresponding to the known symbols may be given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols may be given less weight in the adaptation algorithm.

Abstract: Methods and systems for transmitting a spectrally efficient signal. The method includes frequency modulating an input signal in a transmitter to generate a first frequency modulated (FM) signal and generating in the transmitter an amplitude modulated (AM) component based at least on the input signal. The method may then include generating a second FM signal based at least on the AM component and the first FM signal and sending the second FM signal to a receiver.

Abstract: The present invention provides a method and an apparatus for eliminating direct current offset.

Abstract: Binary Offset Carrier (BOC) is the agreed modulation for signals of next generation Global Navigation satellite systems (GNSS). Compared to current phase shift keying (PSK) modulation by a code, there is a further modulation by a sub-carrier. There is a known major difficulty with BOC called ‘false lock’ where early/late gates settle on the wrong peak of the multi-peaked correlation function. This invention eliminates the problem by eliminating that correlation. Instead, a two dimensional correlation is tracked independently to realize a dual estimate. An unambiguous lower accuracy estimate derived from the code phase is used to make an integer correction to a higher accuracy but ambiguous independent estimate based on the sub-carrier phase. The actual receiver may adopt a triple loop, instead of the usual double loop, where carrier phase, sub-carrier phase and code phase are tracked independently but interactively.

Abstract: By using circularly-arranged signal points obtained by rearranging a part of signal points arranged in a rectangular shape or a cross shape, average signal power and peak signal energy are reduced to improve nonlinear distortion characteristics. Provided is a bit mapping method in which an average value of a Hamming distance in terms of a specified lower bit portion between adjacent signal points is small, and a Euclidean distance between signal points at which the lower bit portions assigned thereto coincide with each other becomes maximum. By applying error correction code only to the lower bit portion, a data transmission method excellent in bit error rate characteristics is provided while suppressing a band expansion rate.

Abstract: We describe an ultra wideband (UWB) orthogonal frequency division multiplexed (OFDM) modified dual carrier modulation (MDCM) decoder comprising: first and second inputs to input first and second signals for first and second OFDM carriers; third and fourth inputs for respective third and fourth signals comprising channel quality estimates for the OFDM carriers; a set of integer arithmetic units coupled to said first, second, third and fourth inputs to form a set of intermediate terms; a first set of adders to form first and second sets of combinations of said intermediate terms, one for each MDCM coded bit value; a compare-select stage to select a first and second minimum valued said combination of said intermediate terms from said first and second set; and a subtracter to determine a log likelihood ratio (LLR) value for said bit from said first and second minimum valued combinations.

Abstract: A Coded Orthogonal Frequency Division Multiplexing (COFDM) communication systems is implemented in which each subcarrier data stream is individually FEC encoded instead of FEC encoding the overall input data stream as implemented in conventional COFDM systems. Specifically, each subcarrier is independently encoded using pseudo orthogonal QPSK M-QAM FEC modulators, transmitted, and decoded using pseudo orthogonal QPSK M-QAM FEC demodulators. Multiplexers and demultiplexers randomize subcarrier symbols across all subcarriers to prevent contiguous subcarrier data errors due to fading or corruption by narrowband interference. This technology can be applied to many wireless and wired communication systems including wireless underwater RF communications.

Abstract: A transmitter-receiver pair encode data as transmitted symbols according to knowledge about variations in noise immunity between different bit positions of the symbols as a decoded. High usefulness data may be preferentially encoded at those bit positions having greatest noise immunity to improve transmission effectiveness.

Abstract: A base station selects a subset of at least one geographically separated antennas for each of the plurality of user equipments. The base station forms at least layer of data stream including modulated symbols, precodes the data stream via multiplication with the NT-by-N precoding matrix where N is the number of said layers and NT is the number of transmit antenna elements and transmits the precoded layers of data stream to the user equipment via the selected geographically separated antennas. The base station signals the subset of the plurality of geographically separated antennas via higher layer Radio Resource Control or via a down link grant mechanism. The base station optionally does not signal the subset of the plurality of geographically separated antennas to the corresponding mobile user equipment.

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: Methods and apparatus are provided for transmitting data in a broadcasting system. Input data is encoded by an encoder. A first demultiplexer generates first transmission symbols using the encoded data. The first transmission symbols are modulated, and the modulated first transmission symbols are transmitted. A second demultiplexer generates second transmission symbols using at least a portion of the encoded data. The second transmission symbols are modulated and the modulated second transmission symbols are transmitted.

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: Provided is a relay node that performs network coding with respect to signals transmitted from a plurality of sources. The relay node may partition a plurality of constellation points into a plurality of subsets, generate a new constellation diagram based on respective characteristics among the plurality of subsets, and perform network coding based on the new constellation diagram.

Abstract: Disclosed herein are methods and techniques for reducing phase slips in optical communications systems and in particular methods and techniques that operate in receivers for a coherent communication system transmitting modulated data symbols exhibiting N-ary symmetrical constellation and predetermined reference symbols.

Abstract: According to one embodiment, a method of encoding a plurality of orthogonal frequency division multiplexing (OFDM) signals is disclosed. The method includes: modulating the plurality of OFDM signals according to a modulation scheme, wherein the modulated OFDM signals are mapped to a first axis and a second axis perpendicular to the first axis, and correspond to a first constellation having a plurality of points symmetric with respect to the first axis and the second axis; and differentially encoding the plurality of OFDM signals according to a second constellation plurality of points defined by shifting a position of one of the first constellation plurality of points toward an origin located at an intersection of the first axis and the second axis.

Abstract: Systems and methods are provided for channel estimation using linear phase estimation. These systems and methods enable improved channel estimation by estimating a linear channel phase between received pilot subcarrier signals. The estimated linear phase can then be removed from the received pilot subcarrier signals. After the estimated linear phase is removed from the received pilot subcarrier signals, a channel response can be estimated. A final estimated channel response can be generated by multiplying the results of the linear channel estimation by the estimated linear phase.

Abstract: Embodiments of the present invention provide an information transmission method and device. The method includes: reporting, by a UE, a CQI value to an eNB; receiving, by the UE, an MCS value sent by the eNB, where the MCS value is determined by the eNB according to the CQI value; and receiving, by the UE, PDSCH data according to the MCS value, where the CQI value and the MCS value are determined according to a second set of tables, where a modulation scheme that can be supported by the second set of tables is higher than 64QAM. The embodiments of the present invention can improve system performance and reduce waste of feedback resources.

Abstract: Embodiments of a system and method for generating a shaped cyclic time-domain waveform are generally described herein. In some embodiments, a first transform may be performed on an input symbol vector to generate a transformed input vector in a transform domain. The transformed input symbol vector may be expanded to generate an expanded symbol vector. At least some elements of the expanded symbol vector may be weighted with a weighting vector selected for pulse shaping to generate a weighted symbol vector. A second transform may be performed on the weighted symbol vector to generate an output symbol vector for subsequent processing and transmission. The second transform may be an inverse of the first transform and may comprise a greater number of points than the first transform.

Abstract: Methods and apparatus are disclosed for receiving a diversity transmitted signal using a Rake or G-Rake receiver in a radio system. Signals are diversity transmitted in a first and second symbol period by two or more antennas. One or more receive antennas receive the diverse transmit signals. Weights are generated to account for the correlation between the channels over which the diverse transmit signals are transmitted in the first and second symbol period and are used to weight the received signals. The weighted signals are then fed to a mutual receiver.

Abstract: A desired signal and interfering signal are transmitted in the same timeslot and on the same frequency using an Adaptive Quadrature Phase Shift Keying (AQPSK) modulated carrier. When the Subchannel Power Imbalance Ratio (SCPIR) for the AQPSK modulated carrier is large and favors the interfering signal, SIC is used to cancel the interfering signal from the received signal. Following interference cancellation, the desired signal is demodulated using two different estimates of the channel and the demodulated soft bits from demodulated soft bits from each demodulation process are combined to obtain a combined estimate.

Abstract: Methods and systems to mitigate impulse interference in an OFDM QAM signal. A per-symbol noise measure, or quality measure (QM) is computed for a symbol k as a MSE of distances between carriers in the symbol and points of corresponding QAM constellations. MSE(k) is averaged over multiple symbols to compute a background signal QM, AVG_MSE(k). If MSE(k) exceeds AVG_MSE(k) by a moderate amount, symbol k may be moderately affected by impulse interference, and per-carrier SNR estimates are downgraded for all data carriers in symbol k, prior to LLR computation. SNR downgrading may be linear or step-wise based on an extent to which MSE(k) exceeds AVG_MSE(k). If MSE(k) exceeds AVG_MSE(k) by a significant amount, symbol k may be significantly affected by impulse interference, and LLRs may be set to indicate that all data carriers are erased in symbol k.

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 a-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: A system and method including a parity bit encoder for encoding each n bits of data to be transmitted with a parity check bit to produce blocks of n+1 bits (n information bits plus one parity bit associated with the n information bits). Each of the blocks of n+1 bits are Gray mapped to a plurality of associated QAM symbols that are modulated onto an optical wavelength and transmitted to a receiver. A maximum a posteriori (MAP) decoder is used at the receiver to correct for cycle slip. Phase errors of 180 degrees may be detected by independently encoding odd and even bits prior to Gray mapping, and identifying errors in decoding odd numbered bits at the receiver.

Abstract: A method and an apparatus for modifying a complex-valued signal are described, the complex-valued signal representing a first symbol and a second symbol. A signal trajectory of the complex-valued signal between the first and second symbols is determined, and, if the signal trajectory passes nearby the constellation origin, the signal trajectory is altered to run closer to the constellation origin.

Abstract: An image rejection (IR) circuit is configured to receive a complex signal from a radio frequency (RF) mixer, where the complex signal includes an in-phase signal portion and a quadrature signal portion. This IR circuit may include: an in-phase path to remove first mismatch information from the in-phase signal portion and associated with at least one in-phase multi-tap filter; a quadrature path to remove second mismatch information from the quadrature signal portion and associated with at least one quadrature multi-tap filter; and a correlation unit to independently update each of the multiple taps of the in-phase multi-tap filter and the quadrature multi-tap filter according to a priority scheme.

Abstract: A method for generating a codebook includes applying a unitary rotation to a baseline multidimensional constellation to produce a multidimensional mother constellation, wherein the unitary rotation is selected to optimize a distance function of the multidimensional mother constellation, and applying a set of operations to the multidimensional mother constellation to produce a set of constellation points. The method also includes storing the set of constellation points as the codebook of the plurality of codebooks.

Abstract: Systems and methods to optimize QAM transmission are provided. In some implementations, a QAM transmitter can operate to optimize QAM transmissions by reducing high peak signals levels via a QAM subgroup inversion. In additional implementations, systems and methods can provide for a QAM transmitter to optimize QAM transmissions by applying a recursive inversion process of QAM blocks to minimize peak output. In still further implementations, systems and methods can provide for a QAM transmitter to optimize QAM transmissions by suppressing QAM subgroups in a circular QAM constellation. Optimizing QAM transmission can provide enhancement in power efficiency of active transmission equipment thereby avoiding high peak signal levels and reducing the instances of clipping.

Abstract: A method may include receiving a positive in-phase (“I”)-channel signal (“I+ signal”), a negative I-channel signal (“I? signal”), a positive quadrature-phase (“Q”)-channel signal (“Q+ signal”), and a negative Q-channel signal (“Q? signal”). The method may further include outputting a truncated I+ signal, a truncated I? signal, a truncated Q+ signal, and a truncated Q? signal. The method may further include generating the truncated I+ signal based on the I+ and Q+ signals and a complement of the truncated Q? signal, generating the truncated I? signal based on the I? and Q? signals and a complement of the truncated Q+ signal, generating the truncated Q+ signal based on the I? and Q+ signals and a complement of the truncated I+ signal, and generating the truncated Q? signal based on the I+ and Q? signals and a complement of the truncated I? signal.

Abstract: Array amplitude modulation which includes mapping a data symbol to a phase modulation signal and an amplitude modulation signal for transmission from antenna elements; applying the phase modulation signal to the antenna element amplifiers; and generating a pattern of enabling/disabling the antenna element amplifiers as a function of the amplitude modulation to produce a phase and amplitude modulated transmission from the antenna elements.

Abstract: Disclosed is a transmission method of transmitting at least one multicarrier signal made up of OFDM-OQAM symbols to a receive antenna of a receiver device, the transmission method being for use by a transmitter device having at least one transmit antenna. In one embodiment, the method comprises, for each transmit antenna of the transmitter device, filtering OFDM-OQAM symbols associated with the transmit antenna using a time-reversal prefilter defined from an estimate of the transmission channel between the transmit antenna and the receive antenna and transmitting the filtered OFDM-OQAM symbols via the transmit antenna over the transmission channel.

Abstract: An optical transport system in which (i) an optical transmitter is configured to adaptively change an operative constellation to use a constellation that provides optimal performance characteristics for the present optical-link conditions and/or (ii) an optical receiver is configured to change shapes of the decision regions corresponding to an operative constellation to adapt them to the type of signal distortions experienced by a transmitted optical signal in the optical link between the transmitter and receiver. Under some optical-link conditions, the optical receiver might use a decision-region configuration in which a decision region corresponding to a first constellation point includes an area that is closer in distance to a different second constellation point than to the first constellation point.

Abstract: An OFDM receiver receives OFDM symbols in the frequency domain and comb filters and then punctures the OFDM symbols to leave symbols with actual pilot information and with null values at the data symbols. The receiver provides the punctured OFDM symbols to an OFDM symbol queue. A virtual pilot interpolator is coupled to the punctured OFDM symbol storage to generate virtual pilot information introduced to OFDM symbols. The interpolator may be a two dimensional Wiener filter. The receiver also includes a time domain channel estimator that processes a first OFDM symbol including virtual pilot information to generate a channel impulse response for the first OFDM symbol. A frequency equalizer equalizes the OFDM symbol in response to the channel impulse response for the first OFDM symbol.

Abstract: A modulator generates a baseband digital signal from an information-bearing digital signal. The baseband signal has time-varying phase and amplitude defined by a sequence of complex data words, each having an in-phase (I) component and a quadrature (Q) component. A noise-shaping modulator generates a noise-shaped digital signal from the baseband digital signal such that quantization noise in the noise-shaping modulator is attenuated by a spectral null of its noise transfer function. The spectral null is selected by a noise-shaping parameter corresponding to a selected one of a plurality of output frequencies. A signal converter generates an analog signal conveying the information of the information-bearing digital signal on an analog carrier signal having the selected output frequency.

Abstract: Techniques for performing spectral shaping to achieve a desired peak-to-average ratio (PAR) are described. Spectral shaping may be selectively performed for a single-carrier frequency division multiplexing (SC-FDM) signal based on one or more criteria, e.g., in transmit power limited conditions and/or if a modulation scheme with lower PAR is unavailable. At least one parameter of a window function or spectral shaping filter may also be adjusted based on at least one characteristic of the SC-FDM signal. For example, the roll-off of the spectral shaping filter may be adjusted based on the modulation scheme and/or the number of subcarriers used for the SC-FDM signal. A transmitter may perform spectral shaping on modulation symbols, if enabled, to obtain spectrally shaped symbols. Spectral shaping may be performed in the frequency domain either within an allocated bandwidth or with bandwidth expansion. The SC-FDM signal may be generated based on the spectrally shaped symbols.

Abstract: Embodiments of the present invention provide an apparatus comprising a transceiver having a receiver and a transmitter connected through a segment of a calibration loop back path. The apparatus also comprises a control system configured to communicate with the transceiver. The calibration loop back path has an intentional phase shift that can be toggled between an off state and an on state by the control system. The control system is configured to calculate the intentional phase shift by examining the difference of a first and second phase angle. The first phase angle is obtained from the transmission of a first pair of signals with the intentional phase shift in the off state. The second phase angle is obtained from the transmission of a second pair of signals with the intentional phase shift in the on state.

Abstract: A system and method for detecting burst noise during quadrature amplitude modulation (QAM) communications are provided. A QAM signal is acquired at a receiver in communication with a network. The QAM signal is demodulated at the receiver to identify a plurality of symbols. Amplitudes for each of the plurality of symbols are determined, and are compared to a predetermined threshold. For each amplitude that is greater than the predetermined threshold, information is recorded at the receiver relating to a burst noise event. The magnitude of the burst noise can be determined by measuring a difference between a received constellation point and a perimeter constellation point closest to the received constellation point. The information about the burst noise event can be transmitted to an error correction module for reducing future burst noise in the network. Equalizer coefficients and tracking loop performance can be adjusted/enhanced using the burst noise information.

Abstract: This invention concerns soft-decision demapping of Quadrature Amplitude Modulation (QAM) signals to enable soft-decision channel decoding in a communications system. In a first aspect the invention is a method for performing the soft-decision demapping of Quadrature Amplitude Modulation (QAM) signals to enable soft-decision channel decoding in a communications system. The method comprises the steps of Extracting baseband signals from both I-and-Q channels. Sampling the baseband signals to extract a stream of complex numbers. Converting the stream of complex numbers to frequency domain vectors with components for each subcarrier frequency. Approximating bit log-likelihood ratios for each symbol directly from the real and imaginary parts of the corresponding frequency vector, without equalization by the estimated channel. And, soft-decoding of the channel codes using the approximated log-likelihood ratios.

Abstract: Embodiments of the present disclosure describe methods, apparatuses, and systems related to use of interphase/quadrature component layer shifting in open loop multiple-input, multiple-output communications. Other embodiments may be described and/or claimed.

Abstract: An apparatus for receiving signals includes a receiver for receiving a time domain signal from a transmitter, wherein at least one first information bit is mapped, resulting in at least one first mapped symbol; at least one second information bit is mapped, resulting in at least one second mapped symbol; the at least one second mapped symbol is multiplied by at least one third information bit; and the time domain signal is generated from the at least one first mapped symbol and the at least one second mapped symbol.

Abstract: When a determination is made that communication by an SM scheme is suitable, a setting unit performs switching from a communication level by an STC scheme to the communication level by the SM scheme, between the communication level at a first level of MCS by the space-time coding scheme and the communication level at a second level of MCS by the SM scheme. When a determination is made that communication by the SM scheme is unsuitable, the setting unit performs switching from the communication level by the STC scheme to the communication level by the spatial multiplexing scheme, between the communication level at a third level of MCS, which is higher than the first level, by the space-time coding scheme and a fourth level of the modulation scheme and the coding rate, which is higher than the second level, by the SM scheme.

Abstract: Techniques for rotating and transmitting multidimensional constellations are disclosed. A method for rotating a multidimensional constellation may include constructing a first rotation matrix, constructing a second rotation matrix, applying orthogonality constraints to the first and second rotation matrices; selecting an optimizing rotation matrix from the first and second rotation matrices; and rotating the multidimensional constellation using the optimizing rotation matrix. Constructing the first rotation matrix and second rotation matrices may include constructing a first column that includes first matrix elements based on the number of axes in the multidimensional constellation, and additional columns that include permutations of the first matrix elements.

Abstract: The proposed invention teaches basic principles of “orthonormal transform” to be used to convert a set of discrete samples into a set of coefficient real samples that is contained in a finite field. The number of real values in each coefficient samples is finite and coded for transmission using digital modulation. It also teaches that handling of multi-path fading of Doppler effects implies that the Bit Error Rate (BER) performance as a function of Bit Energy/Noise (Eb/N0) is close to the performance of Additive White Gaussian Noise (AWGN) channel. The effect of impairments is minimized and only the effect of thermal noise (AWGN) is maintained. The inventive apparatus is simple and maintains constant end-to-end response time, sustainable effective data rate and bounded error performance which is conducive to specify a Quality of Service (QoS) which is useful for service provisioning.

Abstract: A receiver, in particular a VAMOS receiver, is provided. The receiver is adapted to split the complex-valued baseband signal into its real and imaginary parts. The two branch system thus created is modeled as a real-valued Multiple Input Multiple Output, MIMO, system. The receiver is further adapted to use correlations of the noise, both in time and between branches of a channel to suppress the noise for multi-users in the same channel. In accordance with one embodiment the receiver is adapted to take into account the known symmetries present in a symbol constellation when more than one user exists in the same channel. This is for example the case in adaptive symbol constellation such as an adaptive alpha-QPSK constellation. Using the receiver in accordance with the above can provide the same performance as a joint detection receiver in the presence of Gaussian white noise, while giving better interference suppression than either SAIC or joint detection in the presence of GMSK modulated interference.

Abstract: A communications device includes a transmitter, a transmission processing device, a receiver, and a reception processing device. The transmission processing device assigns signal-space points within an I/Q signal space to digital signals, which include data values. The reception processing device assigns data values to signal-space points. The transmitter generates a transmission signal from signal-space points to be transmitted. The receiver determines received signal-space points from a received signal. The individual transmitted and received signal-space points provide in each case a smaller spacing distance from adjacent signal-space points than from the origin of the signal space.

Abstract: A system and method for mitigating Analog to Digital (A/D) clipping is disclosed. The mean and variance of analog input data are tracked and the bits of A/D are dynamically reassigned to keep the input signal within their range. The quantization levels of A/D are dynamically re-mapped to avoid changes in sensitivity of sensor system. The method is based on random walk statistic and keeps the sensitivity of the sensor system constant. Also the system and method provides a way to mitigate A/D clipping that avoids changing the sensitivity by dynamically re-mapping the quantization levels of the A/D, keeping the sensitivity of the system constant.