Abstract: This invention describes a blind speech user interference cancellation receiver for a high-speed downlink packet access (HSDPA). The key component of the blind SUIC receiver is a joint estimation on hard-decision HSDPA signals and soft-decision interfering speech user (ISU) signals with a full Walsh transform correlator used instead of the conventional RAKER, where the outputs are separated into two parts: the desired HSDPA signal with known spreading codes and the ISU signal with unknown spreading codes. The invention further describes a multistage processing for reaching a targeted convergence rate or a desired bit-error-rate for a received signal involving a hard-decision on the desired HSDPA signal and a soft-decision on the ISU signal.

Abstract: Thus, the exemplary embodiments of the invention describe methods, computer program products and apparatus that provide improved quantization, as may be useful within the context of a communication system (e.g., a wireless communication system) that has a relay node. In one non-limiting, exemplary embodiment, a method includes: receiving a transmission having source data from an information source; determining an estimate of the source data using a quantization technique based on maximizing data throughput; and transmitting a message including the determined estimate towards an information destination.

Abstract: In a multiple-input multiple output (MIMO) system, high-rate data transmission is achieved by dividing the original data stream into several parallel data substreams, each of which is transmitted from a corresponding transmit antenna (spatial multiplexing) and received by multiple receive antennas. The number of spatial streams depends on the number of antennas. In a receiver, a search-tree based QR Decomposition-M (QRD-M) algorithm is used. According to the invention, multiple spatial signal streams received from a MIMO channel are pre-ordered based on modulation alphabets of said received spatial signal streams prior to performing a QRD-M detection.

Abstract: A QRD-M decomposition includes a first and a sequential second stage, at least. In the first stage, M branches are selected from among more than M branches entering the first stage as survive branches from which multiple decompositions are calculated. In the second stage, more than M branches are selected from among those branches entering the second stage as survive branches from which multiple decompositions are calculated. The symbol of the received signal is decided from a branch that is a survive branch of both the first and second stages. The second stage may be within a window that may include additional stages at which the pruning decision down to M survive branches is delayed. One or more windows may be used in a single QRD-M decomposition. In an embodiment, all branches entering the second stage are survive branches. It is shown that the marginal increased computational load increases accuracy.

Abstract: A signal constellation for wireline or wireless multi-carrier communication systems, such as systems using OFDM or MC-CDMA, has points separated from one another by maximizing a distance between conditional probability distributions, such as a Kullbeck-Leibler (KL) distance. Preferably, the constellation points are arranged in concentric circles, with or without a point at the origin, wherein adjacent circles are rotated to maximize an angular distance between points on adjacent circles. Pilot symbols inserted in the transmitted signal are used by a receiver to estimate the channel of the multi-carrier system. Different constellations show optimum performance for different signal to noise ratios, and for different numbers of taps used to estimate the channel, especially in a fast fading environment where there may be fewer pilots per OFDM or MC-CDMA symbol than channel taps.

Abstract: A method of transferring data from a first device to a second device, the method including receiving information at the second device; and converting first data, from the first device, from the time domain to the frequency domain using butterfly computations to produce second data, wherein the butterfly computations used are a subset of the available butterfly computations and are selected using the received information.

Abstract: An approach is provided for subblock-wise frequency domain equalization, wherein a data block of a received signal is segmented into at least two subblocks at a receiving end of a transmission channel. The subblocks are then equalized separately in the frequency domain, and equalized subblocks are combined to obtain an equalized signal. Thereby, Doppler induced interference can be suppressed to achieve enhanced robustness to high Doppler and compensate performance degradation due to rapidly varying channels.

Abstract: A method and device for estimating a target chip index value in a code-division multiple access receiver. The receiver receives signals from a transmitter that uses a plurality of transmitted chips for data transmission through a plurality of multipath channels. As each channel is expressible as a channel impulse response at a given instant in time, the impulse response can be sampled and the samples indexed by a plurality of delay sample indices. The target chip index value can be determined based on the first moment of the delay sample indices over an impulse response.

Abstract: A new multiuser detection scheme EPIC (Equalized Parallel Interference Cancellation) is disclosed. A rake receiver signal zRake output by a rake receiver is detected, which receives a spread spectrum composite signal r comprising plural user signals b1,b2, . . . ,bK that have been spread with spreading codes. At first, first hard-decision values bRake are produced on the basis of the rake receiver outputs. Then, first parallel interference cancellation values are produced on the basis of the first hard-decision values, and second hard-decision values bPIC are produced on the basis of the first parallel interference cancellation values. After that, the first and second hard-decision values are combined for producing first combination values, and second parallel interference cancellation values are on the basis of the first combination values.

Abstract: A multi-level space time signal constellation that is optimized for use with a multi-carrier, multi-path communication scheme includes points on a first level separated from points on a mutually exclusive second level by a minimum distance that is based on a conditional probability distribution, preferably a Kullback-Leibler (KL) distance. Points within one level may be separated by a Euclidean distance, but spherical levels are rotated relative to one another to maximize a minimum inter-level KL distance. A receiver uses pilot symbols to estimate the channels and two-stage symbol detection, determining in one stage the constellation level and in another stage the point in the level. The receiver calculates a likelihood function based on a conditional distribution which does not reduce to the Euclidean-based nearest-neighbor detector. A single stored constellation may be scaled based on received signal to noise ratio.

Abstract: A wireless communications system comprising: first and second network entities in communication over a wireless channel, the first network entity comprising means for monitoring signal quality and means for transmitting information relating to signal quality over the wireless channel and the second network entity including a transmitter comprising a basic signal processing system for processing a signal for transmission over the wireless channel, and an enhanced signal processing system for processing a signal for transmission over the wireless channel, the network entity being responsive to said information relating to signal quality to select the enhanced system when the signal quality is below a predetermined threshold.

Abstract: The invention relates to a reception method and a receiver in a system comprising in each cell a base station communicating with terminals located in its area. A received signal comprises a sum signal of signals originating from several transmitters. The receiver comprises means for performing interference elimination and a simultaneous multi-user detection to the signal and means for searching signal parameters. In order to reduce the required computational capacity, the receiver further comprises means for removing the effect of the signals of the known users from the receives sum signal, and means for estimating the parameters of the unknown signals from a narrowband residual signal.

Abstract: A CDMA receiver (10) includes a receiver input for coupling to signal outputs of Nrx receive antennas (20A,20B), where the signal outputs are sampled at Ns samples per symbol or chip, a matched filter (14), such as a RAKE, and a whitening filter (20) for coupling the receiver input to an input of the matched filter. The whitening filter contains NsNrx parallel whitening filters wj,k (22A-22D), individual ones of the whitening filters wj,k receiving during each symbol interval i, NsNrx new signal samples via a signal connection matrix (28) such that a first individual whitening filter receives only one of the new samples, a second individual whitening filter receives the same sample as the first individual whitening filter, and one additional sample, and such that an nth individual whitening filter receives the same n?1 samples as the first n?1 individual whitening filters, plus one of the remaining samples.

Abstract: A method and transceiver for wireless multicarrier communications. At the transmitter side, conventional OFDM symbols, after inverse fast Fourier Transform, are scrambled in time domain and then guard-interval (GI) inserted, up-converted at the carrier frequency for transmission. At the receiver side, after GI removal and frequency domain channel equalization, the received signal is transformed into time-domain by inverse fast Fourier Transform. The time-domain equalized signal is descrambled in time domain and then transformed back to the frequency domain before it is rate-matched, demodulated and decoded. This time-domain scrambling and descrambling method can be used in a wireless OFDM system such as WLAN, cellular OFDM, and MC-CDMA.

Abstract: A multi-level space time signal constellation that is optimized for use with a multi-carrier, multi-path communication scheme includes points on a first level separated from points on a mutually exclusive second level by a minimum distance that is based on a conditional probability distribution, preferably a Kullback-Leibler (KL) distance. Points within one level may be separated by a Euclidean distance, but spherical levels are rotated relative to one another to maximize a minimum inter-level KL distance. A receiver uses pilot symbols to estimate the channels and two-stage symbol detection, determining in one stage the constellation level and in another stage the point in the level. The receiver calculates a likelihood function based on a conditional distribution which does not reduce to the Euclidean-based nearest-neighbor detector. A single stored constellation may be scaled based on received signal to noise ratio.

Abstract: This invention describes a blind speech user interference cancellation receiver for a high-speed downlink packet access (HSDPA). The key component of the blind SUIC receiver is a joint estimation on hard-decision HSDPA signals and soft-decision interfering speech user (ISU) signals with a full Walsh transform correlator used instead of the conventional RAKER, where the outputs are separated into two parts: the desired HSDPA signal with known spreading codes and the ISU signal with unknown spreading codes. The invention further describes a multistage processing for reaching a targeted convergence rate or a desired bit-error-rate for a received signal involving a hard-decision on the desired HSDPA signal and a soft-decision on the ISU signal.

Abstract: The invention relates to a method and a filter for distinguishing signal components from one another, whereof at least one comprises a periodic signal sequence. In the solution samples are taken during several signal sequences (300) and a signal sequence model is formed by arranging the samples taken from several signal sequences (300) together so that the samples represent a single signal sequence (300) model and the signal sequence model is specified by filtering.

Abstract: A signal constellation for wireline or wireless multi-carrier communication systems, such as systems using OFDM or MC-CDMA, has points separated from one another by maximizing a distance between conditional probability distributions, such as a Kullbeck-Leibler (KL) distance. Preferably, the constellation points are arranged in concentric circles, with or without a point at the origin, wherein adjacent circles are rotated to maximize an angular distance between points on adjacent circles. Pilot symbols inserted in the transmitted signal are used by a receiver to estimate the channel of the multi-carrier system. Different constellations show optimum performance for different signal to noise ratios, and for different numbers of taps used to estimate the channel, especially in a fast fading environment where there may be fewer pilots per OFDM or MC-CDMA symbol than channel taps.

Abstract: A CDMA receiver (10) includes a receiver input for coupling to signal outputs of Nrx receive antennas (20A,20B), where the signal outputs are sampled at Ns samples per symbol or chip, a matched filter (14), such as a RAKE, and a whitening filter (20) for coupling the receiver input to an input of the matched filter. The whitening filter contains NsNrx parallel whitening filters wj,k (22A-22D), individual ones of the whitening filters wj,k receiving during each symbol interval i, NsNrx new signal samples via a signal connection matrix (28) such that a first individual whitening filter receives only one of the new samples, a second individual whitening filter receives the same sample as the first individual whitening filter, and one additional sample, and such that an nth individual whitening filter receives the same n-1 samples as the first n-1 individual whitening filters, plus one of the remaining samples.

Abstract: A method and device for estimating a target chip index value in a code-division multiple access receiver. The receiver receives signals from a transmitter that uses a plurality of transmitted chips for data transmission through a plurality of multipath channels. As each channel is expressible as a channel impulse response at a given instant in time, the impulse response can be sampled and the samples indexed by a plurality of delay sample indices. The target chip index value can be determined based on the first moment of the delay sample indices over an impulse response.