Abstract: Methods and apparatus, including computer program products, are provided performance prediction. In one aspect there is provided a method. The method may include receiving information including one or more of a set of weights, a set of events, and a channel estimate, wherein at least one of the set of weights and the set of events are determined based on a optimization; and determining a transmitter configuration by performing at least one of: applying the set of weights to a set of pair wise error probabilities to determine a set of predicted bit error rates, and applying the set of events to the set of pair wise error probabilities to determine a set of predicted packet error rates. Related apparatus, systems, methods, and articles are also described.

Abstract: Methods and apparatus, including computer program products, are provided performance prediction. In one aspect there is provided a method. The method may include receiving information including one or more of a set of weights, a set of events, and a channel estimate, wherein at least one of the set of weights and the set of events are determined based on a optimization; and determining a transmitter configuration by performing at least one of: applying the set of weights to a set of pair wise error probabilities to determine a set of predicted bit error rates, and applying the set of events to the set of pair wise error probabilities to determine a set of predicted packet error rates. Related apparatus, systems, methods, and articles are also described.

Abstract: A resource allocation method for use in a wireless ATM network comprises receiving on a wireless signaling channel a request for access to a shared frequency-time sliced wireless medium. A channel matrix is then searched for a set of available frequency-time slots. The channel matrix represents a time frame within the shared frequency-time sliced wireless medium, and is used to keep track of resource allocation in the time-frequency sliced medium. The set of available time-slots is then allocated if the allocation does not violate a frequency switching constraint, and if the set of available frequency-time slots contains a number of slots no smaller than a requested number of slots. In a preferred embodiment of the invention, the searching step uses a greedy resource allocation strategy to search a channel-chunk matrix comprising a list of contiguous chunks of available time slots in each frequency of the shared frequency-time sliced wireless medium.

Abstract: An inexpensive method and means for generating high power envelope-modulated radio frequency signals is disclosed. Embodiments provide EER amplification and separate modulation of information encoded as phase angle and as amplitude. An envelope modulated signal generation apparatus comprising a source of carrier signal, a source of a binary data stream, a pulse deletion logic and a current switch is disclosed.

Abstract: A method of determining an integral portion of a carrier offset &Dgr;fc of an RF signal transmitted from a transmitter at a transmit carrier frequency fct and an apparatus for carrying out the method. The signal consists of at least two data symbols S1 and S2, each having a useful part preceded by a cyclic prefix containing a tail portion of the useful part, such that in the time domain the useful part occupies a symbol interval Ts and the cyclic prefix occupies a guard interval Tg. The carrier offset &Dgr;fc between a receive carrier frequency fcr and the transmit carrier frequency fct is calculated in the form of an integral multiple of the inverse 1/Ts of the symbol interval. The method is especially useful in application to data symbols which are multiplexed by the orthogonal frequency division multiplexing (OFDM) and are constructed from sub-symbols ck belonging to a 2m-ary constellation of complex values equally spaced in phase, such as phase-shift keyed (PSK) constellations, e.g.

Abstract: A handoff technique for wireless communication systems uses pattern recognition of signal strength data to anticipate handoffs and reduce the total number of handoffs in the system. A criterion for system performance is used in determining the necessity for handoff. A window of signal samples from nearby base stations constitutes a pattern vector which is classified using a probabilistic neural network or other learning machine. The use of averaged signals and the sequencing of classes allow for a small number of training vectors for the pattern classifier. Substantially increased performance requires only one training vector per class. Simulation results indicate that, for a given probability of failure, the pattern recognition based handoff technique yields fewer handoffs than the conventional hysteresis rule.

Abstract: A micro-computer is arranged to execute instructions for data intensive applications, such as those used in mobile communications. One particular embodiment involves processing instructions into computational codes and data management codes. These two parts are coded separately and issued to two different program decoders in parallel. Computational codes control the computational units with register-to-register data movement only. Data management codes control data movement through the data management unit to prepare and transfer data for the computation. Multiple register files with active file swapping scheme may be used to simplify the computational operations without decreasing performance. The arrangement provides a significant reduction in power and is, therefore, especially advantageous for battery-operated communication applications and devices.

Abstract: A method and apparatus achieves rapid timing synchronization, carrier frequency synchronization, and sampling rate synchronization of a receiver to an orthogonal frequency division multiplexed (OFDM) signal. The method uses two OFDM training symbols to obtain full synchronization in less than two data frames. A first OFDM training symbol has only even-numbered sub-carriers, and substantially no odd-numbered sub-carriers, an arrangement that results in half-symbol symmetry. A second OFDM training symbol has even-numbered sub-carriers differentially modulated relative to those of the first OFDM training symbol by a predetermined sequence. Synchronization is achieved by computing metrics which utilize the unique properties of these two OFDM training symbols. Timing synchronization is determined by computing a timing metric which recognizes the half-symbol symmetry of the first OPDM training symbol.

Abstract: In a circuit that detects from a received RF signal the digital signal modulated on the IF carrier signal by recovering the unmodulated IF carrier signal and comparing the recovered IF carrier with the downconverted RF signal, improvements are presented which minimize errors due to rapid and large phase changes in the RF signal. The circuit includes a downconverter (104) for downconverting the received RF signal to the IF level and a phase-locked loop (115, 118, 116, 119, 117) for both providing correction for relatively slow variations in the RF signal and for deriving the recovered IF carrier signal to which the downconverted IF signal is compared (108). Large and rapid phase changes in the RF signal are detected in a separate loop in the phase locked loop by monitoring (122) the sign and phase of the phase locked loop error signal for signals exceeding a predetermined threshold and rapidly advancing (123) or retarding (124) the phase of the recovered IF carrier whenever the threshold is exceeded.

Abstract: The present invention relates to a portable transceiver and a remote terminal station each using at least two antennas with different polarization transmission capabilities for an adaptive retransmission technique. In the present adaptive retransmission technique, the terminal station transmits the same preamble signal in at least two time slots of a frame period of a time division sequence using the antenna receiving the strongest signal from the transceiver in the immediately prior frame period followed by a binary message signal using the same antenna. The transceiver receives each of the preamble transmissions from the terminal station via a separate one of differently oriented antennas and determines which antenna received the strongest signal. The message signal from the terminal station is then received via the antenna of the transceiver having received the strongest signal and also sends its response message signal on that antenna during a separate time slot of a frame period.

Abstract: The present invention relates to a linear, class A FET amplifier circuit capable of providing linear amplifier of input signals with a time-varying envelope function. An envelope detector (12) is responsive to an input signal (v.sub.i (t)) for extracting the envelope signal (V.sub.i (t)) therefrom. A gate controller (16) subsequently adds the envelope signal to a predetermined gate bias voltage (E.sub.G) and applies the sum (E.sub.G (t)) as the "d-c" gate input to the FET amplifier (14). Therefore, the gate bias voltage is dynamically controlled by the envelope of the input signal, resulting in a significant improvement in the power-added efficiency (.eta..sub.added) over prior art class A FET amplifiers.