Abstract: 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.

Abstract: Systems and methods for improving the reliability of a hub-spoke communications system use a first antenna and a second antenna at the hub terminal. Spread spectrum transmission from the hub terminal uses the first antenna, and the second antenna is enabled when blockage between the first antenna and any one of the spoke terminals is present. The first antenna and the second antenna have substantially orthogonal polarizations. The spread spectrum transmissions from the first antenna and second antenna have different pseudonoise code timing so that the received transmissions are offset by at least one chip interval from each other.

Abstract: 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.

Abstract: 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.

Abstract: A method, computer program product, apparatus and system are provided. In one exemplary embodiment, a method includes: receiving at a second unit periodic energy bursts transmitted by a first unit; blanking a transmitter of the second unit in accordance with the received periodic energy bursts such that the transmitter is unable to transmit when the second unit is receiving a periodic energy burst; and transmitting a plurality of instances of a same data from the second unit to the first unit.

Abstract: A method and system for managing Priority Messages in a hybrid TDMA-Spread Spectrum (TDMA-SS) communication system is provided. The method and system include a HUB for generating a HUB TDMA epoch, wherein the HUB TDMA epoch includes at least one Priority Message (PM) slot. The PM slot includes a plurality of assignable PM sub-slots. The method and system also include at least one SPOKE, wherein the at least one SPOKE is adapted to transmit a Priority Message during its assigned PM sub-slot within the HUB TDMA epoch.

Abstract: 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).

Abstract: A system for TDMA-SS signal prioritization and collision mitigation is provided. The system includes a Hub transceiver having plurality of parallel PN correlation branches, wherein each of the plurality of parallel PN correlation branches is prioritized with respect to each of the other plurality of parallel PN correlation branches. The system also includes a first Spoke transmitter adapted to transmit a first prioritized PN encoded signal corresponding to a first one of the first plurality of prioritized parallel PN correlation branches. In addition, a second Spoke transmitter is adapted to transmit a second prioritized PN encoded signal corresponding to a second one of the first plurality of prioritized parallel PN correlation branches.

Abstract: A system for fast data encryption/decryption is provided. The system includes a transmitter system having a transmitter direct digital synthesizer (DDS). The DDS includes at least three transmitter pseudo-noise (PN) component code generators PNx, PNy, PNz, where each transmitter PN component code generator is adapted to generate relatively prime transmitter PN component codes when compared with each of the other transmitter PN component code generators. The transmitter also includes a first processor coupled to the transmitter DDS, where the first processor is adapted to determine a time slot number (TSN) relative to at least two of the relatively prime transmitter PN component codes. Also included in the transmitter is an encryptor for encrypting clear data in accordance with the TSN. The system includes a receiver system having a second processor adapted to determine the TSN; and a decryptor coupled to the second processor.

Abstract: A method and system for determining Psuedo-Noise (PN) composite phase is provided. The method includes providing at least three relatively prime PN component codes and partially correlating a received PN composite encoded signal with one of the PN component codes. The method also includes partially correlating the received PN composite encoded signal with a second one of the PN component codes while maintaining phase alignment of the first partially phase aligned PN code through the use of normalized autonomous phase numbers (NAPNs). The received PN composite encoded signal is then phase aligned with a receiver PN composite code phase in steps of epoch lengths of the partially phase aligned PN component codes.

Abstract: 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.

Abstract: 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.

Abstract: A method and system for synchronizing the PN phase of a pseudo-noise (PN) coded signal with a phase of a master PN decade-code is provided. The method includes the steps of associating the master PN decade-code initialization t0 with a first time zone reference date and time and determining an elapsed time t1. The next steps equate the elapsed time t1 to a corresponding phase of the master PN code and synchronize the phase of the PN coded signal with the corresponding phase of the master PN decade-code.

Abstract: 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.

Abstract: A method and system for determining Psuedo-Noise (PN) composite phase is provided. The method includes providing at least three relatively prime PN component codes and partially correlating a received PN composite encoded signal with one of the PN component codes. The method also includes partially correlating the received PN composite encoded signal with a second one of the PN component codes while maintaining phase alignment of the first partially phase aligned PN code through the use of normalized autonomous phase numbers (NAPNs). The received PN composite encoded signal is then phase aligned with a receiver PN composite code phase in steps of epoch lengths of the partially phase aligned PN component codes.

Abstract: 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.

Abstract: 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.

Abstract: A method and system for synchronizing the PN phase of a pseudo-noise (PN) coded signal with a phase of a master PN decade-code is provided. The method includes the steps of associating the master PN decade-code initialization t0 with a first time zone reference date and time and determining an elapsed time t1. The next steps equate the elapsed time t1 to a corresponding phase of the master PN code and synchronize the phase of the PN coded signal with the corresponding phase of the master PN decade-code.

Abstract: The present invention applies in a communication system where - a) two vehicles V.sub.A and V.sub.B transmit data to each other intermittently, b) data transmitted from V.sub.A to V.sub.B is modulated in V.sub.A by a PN code PN.sub.1 having a time varying phase .phi..sub.MA and is correlated in V.sub.B by the code PN.sub.1 having a different time varying phase .phi..sub.CB, and c) data transmitted from V.sub.B to V.sub.A is modulated in V.sub.B by a PN code PN.sub.2 having a time varying phase .phi..sub.MB and is correlated in V.sub.A by the code PN.sub.2 having a different time varying phase .phi..sub.CA. With the present invention, the codes PN.sub.1 and PN.sub.2 can have respective nominal frequencies f.sub.1 =1/T.sub.1 and f.sub.2 =1/T.sub.2 that drift in at least one of the vehicles. This drift, is then compensated for by the present invention by sensing, during the data transmissions, the phase shifts .DELTA..phi..sub.MA, .DELTA..phi..sub.MB and .DELTA..phi..sub.

Abstract: A system for decoding an IF signal modulated with 4-ary words generated at a known spreading rate (PN code) comprises a receiver in which four known 4-ary words are generated at the same rate. The system then compares the incoming signals modulated with unknown 4-ary words with each of four known 4-ary words. Only one of the known words will be in phase with a received unknown word. The disclosure describes a system which determines which of the four words is in phase, this being the determinant of the identity of the unknown word.