Abstract: Vector modulation is illustrated. A method includes receiving an input signal. The input signal is split into a first 0° output and a 90° output. The first 0° output is split into a second 0° output and a first 180° output using a continuous transmission line. The 90° output is split into a third 0° output and a second 180° output using a continuous transmission line. The second 0° output, the first 180° output, the third 0° output, and the second 180° output are modulated. The modulated second 0° output, the first 180° output, the third 0° output, and the second 180° output are recombined to produce an output signal, where all four of the modulated second 0° output, the first 180° output, the third 0° output, and the second 180° output are used to create the output signal.

Abstract: An angle of arrival system can be self-calibrating. The angle of arrival system can continuously estimate imperfections caused by the analog RF components and dynamically apply corrections based on these estimates. As a result, an angle of arrival system can employ inexpensive components, will not require factory calibration, but can still perform geolocation with high precision.

Abstract: An angle of arrival system is configured to efficiently measure phase differences. The angle of arrival system includes a master receiver for demodulating the signal received at one antenna and for implementing a tracking loop to identify the timing of symbols within the signal. This timing information can be fed back as a synchronization signal to a despreader in the master receiver and to a despreader in each of a number of slave receivers to synchronize the timing at which each signal is despread. Because despreading is synchronized, the outputs of the despreaders can be used to directly calculate phase differences between each pair of signals. In this way, the slave receivers do not need to implement a demodulator or a tracking loop. When the received signal is a non-spread signal, the phase differences between each pair of signals can be calculated directly from the modulated samples of each pair of signals without despreading.

Abstract: An angle of arrival system can be self-calibrating. The angle of arrival system can continuously estimate imperfections caused by the analog RF components and dynamically apply corrections based on these estimates. As a result, an angle of arrival system can employ inexpensive components, will not require factory calibration, but can still perform geolocation with high precision.

Abstract: An angle of arrival system can be self-calibrating. The angle of arrival system can continuously estimate imperfections caused by the analog RF components and dynamically apply corrections based on these estimates. As a result, an angle of arrival system can employ inexpensive components, will not require factory calibration, but can still perform geolocation with high precision.

Abstract: An angle of arrival system is configured to efficiently measure phase differences. The angle of arrival system includes a master receiver for demodulating the signal received at one antenna and for implementing a tracking loop to identify the timing of symbols within the signal. This timing information can be fed back as a synchronization signal to a despreader in the master receiver and to a despreader in each of a number of slave receivers to synchronize the timing at which each signal is despread. Because despreading is synchronized, the outputs of the despreaders can be used to directly calculate phase differences between each pair of signals. In this way, the slave receivers do not need to implement a demodulator or a tracking loop. When the received signal is a non-spread signal, the phase differences between each pair of signals can be calculated directly from the modulated samples of each pair of signals without despreading.

Abstract: A method for timing a full duplex pulsed wireless communication system between first and second transceivers is disclosed. At least one of the transceivers is mobile. A propagation time between the first and second transceivers is calculated. A pulse period of the first transceiver is set to be twice the propagation time divided by an integer. The second transceiver's pulse period is set to be equal to the pulse period of the first transceiver to enable the first and second transceivers to transmit and receive pulses with a substantially reduced risk of a collision between pulses transmitted from the first and second transceivers.

Abstract: Entry of a terminal into a wireless communications network is facilitated for terminals which may operate in either frequency-division duplex or time-division duplex mode. Join request messages transmitted by the terminals include a duplex capability indicator defining a carrier frequency which can be used to response to the terminals.

Abstract: A method of transmitting a spread spectrum signal in a single communication session between a transmitter and a receiver, stores a series of N unique waveform designs and a hopping sequence in a transmitter memory. A signal is transmitted to a receiver according to the hopping sequence using the plurality of N unique waveform designs. Preferably, each waveform design is characterized by a unique composite spreading code that is formed by at least some of a plurality of constituent code segments. Alternatively or additionally, the waveform designs may differ by any one or more of code length, symbol or chip timing or phase, frame or burst structure, chip offset, modulation, error control coding, encryption scheme, or scrambling code. A transmitter and receiver are also disclosed, as is the concept of appending chips between symbols to expand the universe of unique spreading codes without incurring an increase in processing gain.

Abstract: Entry of a terminal into a wireless communications network is facilitated for terminals which may operate in either frequency-division duplex or time-division duplex mode. Join request messages transmitted by the terminals include a duplex capability indicator defining a carrier frequency which can be used to response to the terminals.

Abstract: A method of transmitting a spread spectrum signal in a single communication session between a transmitter and a receiver, stores a series of N unique waveform designs and a hopping sequence in a transmitter memory. A signal is transmitted to a receiver according to the hopping sequence using the plurality of N unique waveform designs. Preferably, each waveform design is characterized by a unique composite spreading code that is formed by at least some of a plurality of constituent code segments. Alternatively or additionally, the waveform designs may differ by any one or more of code length, symbol or chip timing or phase, frame or burst structure, chip offset, modulation, error control coding, encryption scheme, or scrambling code. A transmitter and receiver are also disclosed, as is the concept of appending chips between symbols to expand the universe of unique spreading codes without incurring an increase in processing gain.

Abstract: A method for asynchronous transmission of communication data between periodically blanked terminals separated by an unknown distance is disclosed. A bursted signal is transmitted from a first terminal with a burst time tB and a burst cycle period T. The bursted signal is received at a second terminal. A bursted response signal is transmitted from the second terminal to the first terminal. The bursted response signal has a burst cycle period of T/2 and includes a pair of response bursts, with each burst in the pair having a burst time tA?T/2?tB. Each burst in the pair of response bursts carries an identical data payload. At least one of the response bursts is received at the first terminal.

Abstract: Entry of a terminal into a wireless communications network is facilitated for terminals which may operate in either frequency-division duplex or time-division duplex mode. Join request messages transmitted by the terminals include a duplex capability indicator defining a carrier frequency which can be used to response to the terminals.

Abstract: A method for transmitting low data rate symbols from a burst radar transceiver is disclosed. The method includes dividing a symbol having a symbol period into a plurality of symbol sections. Each symbol section has a symbol section interval that is less than or equal to a burst interval of the radar transceiver. At least two symbol sections can be transmitted with the burst radar transceiver. Symbol energy can be accumulated from the at least two symbol sections at the communications terminal. Information in the received symbol sections can be identified based on characteristics of the accumulated symbol energy.

Abstract: A method is disclosed for transmitting low data rate symbols from a communications terminal to a burst radar transceiver. A plurality of bursts can be emitted from a burst radar transceiver, each burst having a burst interval and separated by an inter-burst interval. A symbol can be transmitted from the communications terminal to the burst radar transceiver. The symbol has a symbol period that is substantially longer than a radar transceiver burst period comprising the burst interval and the inter-burst interval. Symbol energy can be accumulated during inter-burst intervals at the burst radar transceiver over a plurality of burst periods for approximately the symbol period.

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 is disclosed for transmitting low data rate symbols from a communications terminal to a burst radar transceiver. A plurality of bursts can be emitted from a burst radar transceiver, each burst having a burst interval and separated by an inter-burst interval. A symbol can be transmitted from the communications terminal to the burst radar transceiver. The symbol has a symbol period that is substantially longer than a radar transceiver burst period comprising the burst interval and the inter-burst interval. Symbol energy can be accumulated during inter-burst intervals at the burst radar transceiver over a plurality of burst periods for approximately the symbol period.

Abstract: A method for transmitting bursts of data from a communications terminal to a mobile radar transceiver having inter-burst periods is disclosed. The method includes determining a propagation time between the communications terminal and mobile radar transceiver. A length of inter-burst periods of the mobile radar transceiver having an inter-burst timing can be determined. Bursts of data having a communication burst period that is less than the inter-burst period can be formed. The bursts of data from the communications terminal can be transmitted at a transmission time based on the inter-burst timing and the propagation time to enable each burst of data to be received by the mobile radar transceiver during one of the inter-burst periods.

Abstract: A method for asynchronously transmitting bursts of data from a communications terminal to a burst radar transceiver is disclosed. The burst radar can transmit a plurality of bursts, each separated by an inter-burst interval. An inter-burst interval length of the burst radar transceiver can be established. A burst of data at the communications terminal can be formed having a terminal burst interval length less than half the inter-burst interval of the burst radar transceiver. The burst of data can be transmitted a plurality of times from the communications terminal to the burst radar transceiver.

Abstract: A system and method for transmitting high data rate information from a pulsed radar is disclosed. The method includes collecting information using a mobile radar platform. The information is divided into a plurality of segments. Each segment is configured to fit within a time period less than a radar burst signal time period. Each segment is modulated onto a radar burst signal to form modulated radar burst signals. The modulated radar burst signals are transmitted from the pulsed radar system.