Abstract: Systems and methods for color correcting radiation by alternately focusing a first radiation spectrum on a first radiation spectrum detector, and then focusing at least one additional radiation spectrum on at least one additional radiation spectrum detector.

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: 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: Encoding of a low-density parity check code uses a block-circulant encoding matrix built from circulant matrices. Encoding can include partitioning data into a plurality of data segments. The data segments are each circularly rotated. A plurality of XOR summations are formed for each rotation of the data segments to produce output symbols. The XOR summations use data from the data segments defined by the circulant matrices. Output symbols are produced in parallel for each rotation of the data segments.

Abstract: An apparatus and method for correlating a signal over a correlation interval while accommodating spreading code frequency offset is described. In one embodiment, the apparatus includes a plurality of correlators, where each correlator forms a correlation result corresponding to a unique code frequency offset hypothesis. Each correlator selects samples from a tapped delay line at a tap position moved along the delay line at a rate corresponding to the correlator unique code frequency offset hypothesis.

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: Physical layer quality of service is provided for a wireless communication system by operationally adapting the physical layer format to the quality of service requirements of transmitted data. The physical layer formats for the data packets are selected based on the quality of service requirements of the data packets. Control information defining the formats is transmitted across the wireless communication link and the data packets are transmitted using the selected physical layer formats.

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 system and method for parallel Pseudo-random Noise (PN) code generation is disclosed. The method includes the operation of producing a PN code sequence having a predetermined length. The PN code can be divided into L segments. At least one of the L segments can have a length less than other segments. The L segments can be distributed into an array of L digital memories. Each of the digital memories can output every Lth chip of the PN code in parallel at a selected rate. An element of the PN code can be substituted from an element substitution cache into the output of the L digital memories to compensate for segment(s) having a shorter length.

Abstract: An emergency locating system can include emergency transceivers and rescue transceivers. The emergency transceivers can be capable of repeat transmission of a distress message using a variable power level and variable spreading factor. A receive transceiver can be capable of receiving the distress messages and sending a confirmation message to the emergency transceiver. The emergency transceiver can be capable of receiving the confirmation message and terminating transmission of the distress message.

Abstract: A system and method for designing a full duplex communications transceiver to enable a reduction in isolation between a transmit signal and a receive signal at a diplexer is disclosed. An RFE transmit filter attenuation level can be determined to be sufficient to attenuate a noise power of the transmitter below a thermal noise floor of the power amplifier. A minimum diplexer transmit filter attenuation level can be calculated to attenuate noise power output from the power amplifier in the receive band to a level below a noise floor of the receiver.

Abstract: A compact integrated waveguide load has a load section disposed within an interior region of the waveguide proximate to a closed end of the waveguide. The load section has a tubiform shape, with an exterior surface congruent with an interior surface of the waveguide and an interior surface defining a circumferential step within the waveguide. A method of making a compact integrated waveguide load includes providing a waveguide and placing electromagnetic wave absorbing materially circumferentially around the interior surface to create an inward step.

Abstract: A compact integrated waveguide load has a load section disposed within an interior region of the waveguide proximate to a closed end of the waveguide. The load section has a tubiform shape, with an exterior surface congruent with an interior surface of the waveguide and an interior surface defining a circumferential step within the waveguide. A method of making a compact integrated waveguide load includes providing a waveguide and placing electromagnetic wave absorbing materially circumferentially around the interior surface to create an inward step.

Abstract: A system and method is disclosed for protecting a receiver configured to receive a plurality of contemporaneous spread spectrum signal bursts from a denial of service attack. The method includes the operation of detecting a burst transmission that includes a random burst number. The burst transmission can be analyzed to determine a denial of service statistic based on the random burst number. The burst transmission is processed when the denial of service statistic is within a predetermined threshold.

Abstract: A digital communication system includes a generator for generating a plurality of pulse trains, each having a different timing, and pre-compensation circuitry for synchronizing the plurality of pulse trains to a timing signal. The system also includes comparison circuitry for simultaneously comparing a received burst code signal to each of the plurality of pulse trains, where the burst code signal is synchronized to the timing signal, and a detector for detecting which of the pulse trains is a closest temporal match to the burst code signal. The pre-compensation circuitry operates to reduce acquisition time and keep PN code uncertainties within the range of the comparison circuitry.

Abstract: A technique for resolving access contention in a parallel turbo decoder is described. The technique includes associating a plurality of buffer memories with the subdecoders so that accesses to banks of a shared interleaver memory can be rescheduled. Accesses can be rescheduled to prevent simultaneous accesses to a single bank of the shared interleaver memory based on an interleaver pattern.

Abstract: A mobile distributed antenna array can include a plurality of mobile platforms, each platform having at least one antenna element and radio equipment coupled to the at least one antenna element. The radio equipment can be capable of transmission, reception, or both of propagated radio signals. A control platform can be capable of communication with the mobile platforms to control movement of the mobile platforms to position the mobile platforms relative to each other to provide a desired array pattern.