L-3 Communications Corporation

L3 Corrections Corporation

Michael Rice

Thomas R Giallorenzi

June Y Sun

Samuel Charles Kingston

William K McIntire

Christian B Schlegel

Johnny M Harris

A method for acquiring signals received from multiple users in a single burst groups signals by power and sequentially processes the signal groups. A received sum of a plurality of user signals received in a burst is stored, and the transmitted symbols for each signal within a first group of the stored signals is estimated. A modified set of signals is then determined that excludes the signals of the first group. From the modified set of signals, the method continues by canceling multiuser interference among signals within a second group, and estimating transmitted symbols for each signal within the second group. The first and second groups includes all signals within a power band that defines the group, and the first band represents a higher power band than the second. Such iterative processing may continue for sequentially lower power bands until all signals are processed. A receiver is also detailed.

Multi-user receiver and method for successive acquisition

Disclosed is a method for acquiring a user signal from among several received from multiple users in a single burst. The method includes receiving a plurality of user signals in a single transmission burst, suppressing multiuser interference among at least some of the plurality of received signals, and determining a carrier frequency of at least one signal from among the interference suppressed plurality of received signals. Said signals may rotate due to a lack of synchronization while being equalized. Also described is a multiuser receiver for acquiring at least one user signal from among several user signals received from multiple users in a single burst. An antenna is for receiving a plurality of user signals in a single spread spectrum transmission burst, a matched filter is for despreading the signals, a multiuser equalizer is for suppressing mutual interference among at least a portion of the plurality of user signals, and a carrier lock circuit is for determining a carrier frequency of at least one user signal of the portion.

Non-coherent multiuser receiver and method for aiding carrier acquisition in a spread spectrum system

A method for partitioning communication resource among multiple users partitions a portion of an available communication resource into a series of time-frequency slots, and allows multiple users to transmit in one of at least two available modes within a time-frequency slot. Preferably, one mode is time division of the time-frequency slot into time sub-slots, and another mode is code division of the time-frequency slot according to different spreading codes that spread an individual user's signal only within the subject time-frequency slot. Further details as to pilot signals, guard intervals, and payloads are described.

Hybrid multiple access waveform, method, and apparatus

In an aspect of the invention, a method is performed in a transceiver for adaptive power amplifier linearization in time division duplex communication systems. The method comprises, in response to a first condition, performing, using a feedback signal generated by receiving subsystem circuitry, adaptive power amplifier linearization on a signal to be transmitted. The method additionally comprises, in response to a second condition, performing operations in order to determine receive data from a received radio frequency (RF) signal. The operations use at least the receiving subsystem circuitry. In a further aspect of the present invention, a transceiver is disclosed.

Adaptive power amplifier linearization in time division duplex communication systems

A method and serial detector for demodulating a phase-modulated signal are presented. In particular, a carrier phase estimator applies a phase estimate to an output of a matched serial filter. The filter output is matched to the first Laurent pulse of the received signal, and the phase estimate corrects for a phase bias introduced by using the first Laurent pulse. The method and detector are particularly valuable in Gaussian Minimum Shift Keying (GMSK) modulated systems and where then product of the bandwidth B and the bit rate Tis less than about 0.3, and where a training sequence in a header of a burst system has a length Lless than about 5000. Three estimates of phase offset are given, each taking the inner product of x and the conjugate transpose of either a or p; wherein x is a vector of data samples, a is a vector of pseudo symbols, and p is a vector of the data and ISI portions of the samples.

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Provo, UT, United States of America

Michael Rice