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: Communication of data over a multiple-input multiple-output (MIMO) channel includes allocating transmission power unequally to the different data streams. The transmission power allocation is performed without regard to a state of a changing channel response of the MIMO channel. A relatively low complexity interference cancelling receiver can therefore decode the data streams.

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 system and method for detecting a presence and frequency offset of a spread spectrum radio frequency signal is disclosed. The method comprises receiving the spread spectrum radio signal. The signal can be sampled to form a plurality of signal samples. Each signal sample can be multiplied by a complex conjugate of a proximate signal sample to form a plurality of signal sample pairs. The signal sample pairs can be summed over a predetermined dwell time period to form a data vector having a magnitude and angle offset to enable detection of the signal and to enable a frequency offset between the spread spectrum radio frequency signal and a receiver frequency reference to be determined.

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 and apparatus for detecting a spread spectrum signal is described. Signals can be detected using correlation techniques. When a signal is detected, declaring of signal presence is inhibited for offsets of signal parameters from the parameters of the detected signal, where the offset corresponds to a known sidelobe of the spreading code. This helps to reduce false detections caused by sidelobes of the spreading code.

Abstract: A technique for receiving multiple spread spectrum bursts is disclosed. Each spread spectrum burst is encoded with a common spreading code and may include an individual message and unique signal parameters. The technique includes the detection of the spread spectrum encoded bursts and estimation of the reception signal parameters. A single one of a plurality of burst receivers is assigned to each detected burst to extract the individual message of the detected burst.

Abstract: A system and method for detecting a spread spectrum encoded message within a received signal is described. The spread spectrum encoded message has an unknown code phase, unknown code frequency offset, and unknown carrier frequency offset. A plurality of code phase hypotheses, code frequency offset hypotheses, and carrier frequency offset hypotheses are searched in parallel. The unknown code phase, unknown code frequency offset, and unknown carrier frequency offset may also be estimated.

Abstract: The invention provides a system and method for generating a high rate pseudo-random noise (PN) code with a parallel PN generator. The method includes the operation of configuring L programmable PN generators to each output every Lth chip of a PN code. Select PN generators of the L PN generators can be configured to have their output delayed for a predetermined number of chips less than or equal to L when a fine slip is needed to allow the high rate PN code to be delayed for a set number of chips to synchronize the high rate PN code with another PN code. The outputs of each of the L programmable PN generators can be multiplexed to produce the high rate PN code.

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 system and method for determining a fine frequency offset of a composite code spread spectrum signal is disclosed. The method includes despreading at least one component of the composite spread spectrum signal to form a partially despread composite spread spectrum signal. A set of on-time samples are selected from the signal. The set of on-time samples are rotated by a predetermined frequency amount. The set of rotated samples are placed into a plurality of frequency bins, with each frequency bin representative of a different frequency estimate. An energy for the signal in each frequency bin is determined to find the bin having the greatest energy.

Abstract: A technique for scheduling transmissions for a plurality of transmitters in a TDMA network is described. The technique includes assigning guard time between each pair of successive transmitters, where the guard time is related to the propagation delay between the pair of successive transmitters. Total guard time is minimized by selecting an order of transmission for the plurality of transmitters to minimize the total guard time.

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 is disclosed for PN correlation and symbol synchronization of a spread spectrum signal at a receiver when a symbol boundary of the spread spectrum signal is not on a PN epoch or is otherwise unknown. The method includes the operation of modulating the spread spectrum signal with a PN code to form a potentially despread signal. The potentially despread signal can be integrated for a plurality of symbol times at a rate of N integrations per symbol time to form N symbol energies per symbol for a plurality of symbols. Each of the N symbol energies can correspond to a different symbol time hypothesis. The N symbol energies from the plurality of symbols can be added respectively to form N summed symbol time hypotheses. The Nth summed symbol time hypothesis having maximum power can be found. The Nth summed symbol time hypothesis can relate to a location of the symbol boundary.

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 method and system for optimizing a mobile radio network topology for an N node network where each node has K connecting links. A base network topology is established and a cost value is determined for the base network. It is determined if all possible local transformations on the base network topology have been performed and if not a local transformation is performed on the base network to form a transformed network. A cost is calculated for the transformed network and the cost is compared with the cost of a base network. The transformed network is established as the base network if the cost of the transformed network is less than the cost of the base network.

Abstract: Method and apparatus for maintaining synchronization in a CDMA communication system by operating closed loop timing control between a radio base unit and subscriber units, operating open loop timing control between the radio base unit and the subscriber units, and using timing information derived from the open loop to correct the closed loop. Generally the open loop is faster in response than the closed loop. The open loop timing control may be generated by using GPS data. A radio base station and a subscriber unit operating in accordance with these principles.

Abstract: An apparatus for an improved antenna tracking system for antennas mounted on an unstable platform. The system comprising a directional antenna, an attitude heading reference system (AHRS) mechanically connected to the at least one directional antenna, a self-scan acquisition and tracking method and an antenna controller connected to the AHRS.

Abstract: A method of branch metric calculation of trellis coded data, suitable for a decoder of phase angle on a carrier modulated with phase shift keying (PSK) modulation, begins with an expressing angles of phase shift by a vectorial representation of sectors within quadrants of a circle. The sectors are subdivided into sub-sectors of differing sizes, and the sub-sectors are divided further into equal increments of angle referred to as PIEs. The PIEs and the quadrants are identified and, in each quadrant, there is an assigning of a set of branch metrics to serve as identifiers of respective ones of the sub-sectors in each sector of the quadrant. The set of branch metrics in one sector of the quadrant differs from the set of branch metrics in another of the sectors of the quadrant by a permutation of the branch metrics. The phase data is outputted in the form of branch metrics and quadrant for use by a decoder such as a Viterbi decoder.