L-3 Communications Corporation

Other

L-3 Communications Systems

Kent R Bruening

Vaughn Lee Mower

Merle LeRoy Keller, Jr

Steve J McEntire

Harold L Simonsen

Michael Wilson

Randal R Sylvester

Zachary C Bagley

Clifford T Johnson

Merle L Keller, Jr

Synchronization of a primary link which transitions between clear mode and spread mode is achieved and maintained using a secondary link. When transitioning from clear mode to spread mode, a primary transmission delta phase is adjusted by the difference between a secondary reception delta phase and the primary transmission delta phase; and a primary reception delta phase is adjusted to be equal to a secondary transmission delta phase.

Chip timing synchronization for link that transitions between clear and spread modes

Direct sequence spread spectrum communications can use composite codes and can operate at a plurality of different chipping rates. The composite codes can be formed using a plurality of component codes, wherein the component codes can be relatively prime and at least one of the nominal lengths of the component codes can include a plurality of prime number multiplicands. The chipping rate and code length can be reduced by dividing a master rate by one or more of the prime number multiplicands. Symbol timing and time division multiple access timing can be tied to epochs of the component codes.

Direct sequence spread spectrum system and method with plural chipping rates

A phase division multiple access (PDMA) system is provided. The PDMA system includes at least one receiver logic combiner adapted to generate a plurality of composite PN codes. Each of the plurality of composite PN codes are derived from a common composite PN code and are separated by a predetermined PN phase.

System and method for multi-phase composite PN code generation

A system and method for using Psuedo-Noise (PN) phase to determine frame start of a data frame is provided. The system and method includes at least two PN component codes, wherein the at least two PN component codes are relatively prime. A received PN composite encoded signal is correlated with at least one of the PN component codes and a frame start is determined. With reference to frame start at least one training sequence bit is located. The training bits may be overwritten on FEC encoded frame data such that a FEC decoder may be used to recover data overwritten by the training sequence bit(s).

System and method for predictive synchronization for locating interleaving frames and demodulation training sequences

This invention generates pseudo-noise (PN) codes that map a transmitted data rate into the PN code structure. This invention further then acquires the PN code to automatically discover the transmitted data rate. This invention is operable with communication systems that utilize GPS time synchronization of the transmitted and received PN codes, as well as with communication systems where GPS time synchronization is not available. A method and a system are disclosed to transmit a modulated signal from a transmitter to a receiver, where the modulated signal has a data rate. The method includes selecting, to represent the data rate, at least one PN component code from a set of PN component codes. The PN component code is a constituent code of a composite PN code comprised of a plurality of PN component codes. The selected PN component code is one that phase aligns with a PN composite encoded signal. The method further includes modulating the signal to be transmitted using the PN composite code that includes the selected PN component code, receiving the modulated signal, demodulating the received signal using a demodulation process and discovering the data rate during the demodulation process. The demodulation process includes generating instances of a plurality of PN component codes, and correlating the received modulated signal either sequentially or in parallel with the instances of the PN component codes.

System and method for fast data rate discovery from PN codes

A novel MODEM and method of operating a MODEM usable in spread spectrum communication utilizing multiple waveforms in orthogonal spread signals imbeds a tracking signal in one of the spread signals for efficient tracking by a receiver so that both spread signals can have wideband characteristics. Therefore, one spread signal contains a tracking channel and a wideband channel, allowing for higher order modulation in the wideband channel for transmitting information, while still providing good tracking features. The second spread signal is an orthogonal wideband channel serving as the main high data rate conduit. In the preferred embodiment, the first portion of the waveform (in the first spread signal) is modulated using Bi-Bi-Phase Shift Keying (Bi-BPSK), while the second portion of the waveform (in the second spread signal) is modulated using Multiple Phase Shift Keying (MPSK). The two waveform portions are Time Division Multiplexed (TDM) at the chipping rate. A higher overall data bandwidth can be achieved for the Bi-BPSK modulation technique using the same channel bandwidth.

High rate, time division multiplexed, multi-MPSK MODEM with imbedded high signal-to-noise ratio tracking channel

A communications system comprising a central node, at least one remote node and a communications link. The remote node is adapted to receive information transmitted from the central node over a broadcast link and the communications link is adapted to convey information from the remote node to the central node. The central node is adapted to dynamically tailor a remote node transmit power control and a bandwidth as requested by the remote node for conveying information over the communications link.

Multiple access bandwidth-on-demand using MSPK with an embedded tracking channel

A system for generating (PN) spread signals is provided. The system includes a first clock synchronized with a second clock and at least three first pseudo-noise (PN) component code generators coupled to the first clock. A logic combiner is coupled to the PN component code generators and is adapted to generate a composite PN code. Both clocks are coupled to respective N-bit and M-bit counters.

System and method for generating and acquiring pseudo-noise (PN) spread signals

A method and system for generating a data clock having edge coincidence with an aggregate PN code is provided. The method includes providing an aggregate PN code generator having an epoch output for resetting a data clock generator when the aggregate PN code generator generates an epoch signal. Between resets the data clock generator divides a PN master clock signal with a divisor derived from the prime factor(s) of one or two of PN codes used to form the aggregate PN code.

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Sandy, UT, United States of America

Kent R Bruening