Abstract: A signal detection technique for multiple-input multiple-output (MIMO) communications systems embodied in a method and apparatus for detecting a plurality of transmitted signals with use of a plurality of receiving antennas. An iterative procedure decodes one of a plurality of transmitted signals at each iteration using an intermediate matrix at each iteration to determine the transmitted signal to be decoded. The intermediate matrix for each successive iteration is advantageously computed in a recursive manner with use of a Schur complement operation performed based on the inverse of a modified version of the intermediate matrix used in the previous iteration.

Abstract: Systems and methods are described for pulse communications using precision timing. A method includes digitally pulse coding a data stream; and modulating a carrier signal using the digitally pulse coded data stream.

Abstract: A method transmits packet data in a communications system between a transmitter and a receiver. One potential goal is to ensure correct processing of such packet data. To this end, the packet data are repeatedly transmitted by the transmitter and are received by the receiver as data received earlier or data received later. A diversity combination of the data received earlier and the data received later is performed to reconstruct the transmitted data packet.

Abstract: A diversity receiver in a radio apparatus has at least two reception branches and a RAKE receiver to combine signal received by the different reception branches as well as a measuring receiver to make frequency specific measurements. The radio apparatus includes a switch connected with at least one reception branch and has at least two states in the first of which the switch is arranged to direct a signal received by a reception branch to the RAKE receiver and in the second of which the switch is arranged to direct a signal received by a reception branch to the measuring receiver. The radio apparatus makes measurements at other than the operating frequency without the reception at the operating frequency being interrupted. In a communications system the measurements may be associated with a handover.

Abstract: A demodulation system for receiving and demodulating multiple modulated signals, including a first modulated signal having a first bit rate and/or a first modulation format and a second modulated signal having a second bit rate and/or a second modulation format. The demodulator demodulating the first modulation format modulated signal provides a cross-correlated demodulated in-phase and quadrature-phase baseband signal and the demodulator demodulating the second modulation format modulated signal provides a second demodulated baseband signal. A selector selects either the first or the second or both bit rate and/or modulation format demodulated baseband signals. In an alternative embodiment two demodulators are implemented for the demodulation of multiple signals.

Abstract: Modulation Demodulation (Modem) Format Selectable (MFS) and Code Selectable (CS) systems for new generations of wireless systems, including third generation “3G”, spread spectrum systems, CDMA,W-CDMA and GSM, OFDM systems having different bit rates, that is having bit rate selection or bit rate agile( BRA) operation. MFS and Code Selectable (CS) systems connected to one or more modulators, one or more transmit amplifiers and one or more antennas. The transmitted signals are received by single or multiple receivers and demodulators. Shaped Time Constrained Signal(TCS) wavelet processors and bit rate agile Long Response (LR) filters provide shaped Time Constrained Signal (TCS) waveforms/filtered signals in in-phase(I) and quadrature-phase(Q) baseband channels to one or more Quadrature Modulators(QM) connected to the baseband signal processing network.

Abstract: Communications acquisition method for correlating an incoming binary-coded spread sequence having m bits and arriving at a frequency f with a locally generated spread sequence by phase-shifting a multiplicity of locally generated spread sequences with respect to the received spread sequence. The received spread sequence being correlated with a locally generated spread sequence at the frequency f. The received spread sequence is stored. The received, stored spread sequence is split into sections and the correlation is carried out in steps at an oversampling rate. A correlator includes a shift register with feedback. Register positions of the shift register are connected in parallel to a memory input, and the memory output is connected in parallel with the register positions. A further memory holds reference signal sequences and another comparator compares the memory content with further memory content.

Abstract: A compensation circuit and method for reducing ISI products within an electrical data signal corresponding to a detected data signal received via a signal transmission medium introduces distinct compensation effects for individual ISI products within the electrical data signal. Distinct data signal components within the detected data signal and corresponding to such ISI products can be selectively and individually compensated, thereby producing a compensated data signal in which each selected one of such individual data signal components is substantially removed. Individual data signal components or selected combinations of data signal components can be compensated as desired.

Abstract: A data transmission method includes the steps of: a) performing two-dimensional interleaving along a time axis and along a frequency axis; b) transmitting thus-obtained data by a multi-carrier transmission form; and c) producing, by channel copy operation, data which is short with respect to the required number of channels for fast inverse Fourier transform performed antecedent and subsequent to the step a).

Abstract: This invention discloses a baseband processing method based on smart antenna and interference cancellation. The method includes the steps of: A. making a channel estimation to get a channel response; B. picking up useful symbolic level signals from received digital signals by smart antenna beam forming based on the channel estimation of step A; C. reconstructing the useful symbolic level signals and adding a scrambling code to get the chip level reconstructed signal; D. subtracting the reconstructed signal from the received digital signal; and E. executing steps B to D repeatedly to recover signals for all users. The method of the invention can solve problems associated with interference of multi-path propagation in CDMA systems with smart antennas with better results.

Abstract: An adaptive equalizer comprises a decision device; a decision feedback equalizer coupled to the decision device; an FIR filter coupled to the decision device; and a trellis decoder coupled to the decision device, adapted to provide a reliability output and a decoded output. An error signal is generated by subtracting an output of the decision feedback equalizer from an output of the decision device, the error signal being used to update coefficients of the taps of the FIR filter and the decision feedback equalizer. A magnitude of the change to the coefficients is selected based at least in part the reliability output of the trellis decoder.

Abstract: A multi-line ADSL modem (12) and network (10) whereby the multi-line ADSL modem (12) has connections to several ADSL modems (14) at a central office (CO) (16) through a master loop (18), shared loops (20, 22), and/or broadcast loops (84). The master loop (18) provides the basic connection between the multi-line ADSL modem (12) and the CO modem (14) at the central office (16) while maintaining regular telephone service. The shared loops allow the multi-line ADSL modem to share the transmission capacity with other modems. The multi-line ADSL modem is able to receive broadcast data from the central office where several loops are configured as a broadcast loop for downstream transmission only, but which can also be configured for upstream communication transmission only or in combination with downstream transmission to provide bi-directional broadband communications.

Abstract: A receiving apparatus and method for a synchronizing process in the digital communication system is disclosed. A receiving apparatus includes: a A/D converting unit for performing an over-sampling process and outputting over-sampled points; a sample classifying unit for classifying the over-sampled points; a integration unit for integrating classified symbol values; a symbol synchronizing unit for selecting a point of symbol synchronization; a frequency estimating unit for estimating a frequency error; and a digital demodulating unit for demodulating values outputted from the symbol synchronizing unit and the frequency estimating unit to a signal. The present invention can simplify a configuration of the apparatus and reduce an amount of parameter-control. Moreover, the present invention can be used in a burst mode of a digital communication system.

Abstract: A method, and apparatus implementing the method, encodes bits to be transmitted over a channel. The channel may be a single carrier or a multi-carrier channel. Bits are encoded based on a constellation that has a self-similarity property and also has an improved bit error rate. The constellation was iteratively generated using a mirroring technique. In addition, a method, and apparatus, implementing the method, decodes bits that were received from a channel. The bits are decoded for a constellation that has a self-similarity property and that was generated using the mirroring technique.

Abstract: Method and system for coding/decoding a digital data stream coded with bitwise interleaving in multiple transmission and reception for a radio interface, in which the coding includes subjecting an initial digital data stream to an outer coding, an interleaving, a layer demultiplexing on multiple pathways, converting by modulation successive bits of each layer into Qm-ary symbol then transmitting each symbol by means of a transmission antenna of an array of antennas and the decoding includes receiving the digital data stream transmitted on multiple r reception antennas forming an array, subjecting the set of symbols received to an iterative process of equalization and joint multilayer detection, on the basis of an a priori information item, subjecting the first extrinsic information stream obtained to a deinterleaving, subjecting a second extrinsic information stream obtained to an outer decoding and a third extrinsic information stream obtained to an interleaving so as to generate the a priori information ite

Abstract: Methods and apparatus for reducing phase jitter in a multi-tone, e.g., OFDM, receiver are described. A jitter compensation filter is used to process a received signal following timing recovery and/or channel compensation to reduce and/or eliminate the effect of phase jitter. Jitter compensation filter tap weights are updated after filtering the received signal based on one or more signal error measurements. The same received signal is filtered using the updated filter, and error measurements generated from the filtered signal are used to once again update the filter's tap weights. After a fixed number of filter update cycles and/or some other filter updating stop criterion being satisfied, the filter updating process is stopped and the filtered signal is used, e.g., supplied to additional receiver circuitry.

Abstract: A receiver local oscillator is always tuned to a frequency that lies within a range of reception frequencies of the receiver. The oscillator is tuned to a frequency less than and above the received frequency when the received frequency is above and below a threshold frequency, respectively.

Abstract: A mechanism for dealing with faster clock speeds by increasing the pulse width of the pump-up and pump-down pulses of a Hogge-type phase detector without dividing the clock. In particular, the NRZ data stream is divided into two, interleaved data streams which are provided through two series of flip-flops. By connecting the exclusive-OR gates separately to the two series of flip-flops to generate the pump-up and pump-down pulses, a longer time between transitions can be achieved by having alternate transitions (up and down) used by the two different series of flip-flops. In addition, delay circuits are provided to compensate for the clock-to-data output delay of the flip-flops.

Abstract: A wireless receiver receives signals at a plurality of antennas and the combined signal is compensated for channel distortion. In other aspects, a wireless receiver includes a minimum distance receiver applied to the output of a whitened-matched filter, which combines channel matched filtering and whitening, using one or more antennas.

Abstract: Mobile units in a multicarrier, multidimensional communications system can assess their own channel coherence time attributes (base stations can also access such dynamics for mobile units as well). This information is utilized (either by the mobile unit itself or by an infrastructure component such as a base site) to determine a level of trustworthiness for other channel quality data as might be measured by the mobile unit. Different modulation and coding schemes, along with responsive frequency and time diversity resource allocations, are adaptively selected as a function of this level of trustworthiness.