Abstract: A dual-frequency conformal multi-filiar helical antenna system (20) provides a low-profile, low drag antenna useable in flying equipment. This antenna system (20) securely holds within its shell (22) signal distribution circuitry (64), signal combining circuitry (68), and any other circuit components necessary for antenna system (20) to communicate with other stations or devices. Antenna system (20) has radiating conductors (24, 32) tuned to two different frequencies such that simultaneous transmission and reception of signals is possible in the same and opposite directions.

Abstract: A high speed data transfer system includes a WAU (201) which is utilized to provide high speed access to satellite transferred data. The system is configured such that a plurality of data utilization (205) may access the high speed data via wireless links to the WAU (201). Advantageously, high speed data services may be provided to users without the users requiring individual satellite antennas.

Abstract: Techniques are provided for secure group communications in a wireless dispatch system which includes a group of devices. The group of devices can include a first secure device which communicates with a plurality of second secure devices over a channel.

Abstract: A feed assembly (26) for an antenna system (38) includes a first feed element (30) that propagates a first beam (32) and a second feed element (34) that propagates a second beam (36). The second feed element (34) is collocated with, but displaced vertically from, the first feed element (30) to achieve angular diversity in elevation. Each of the feed elements (30, 34) has an elongated conical shape and is formed from a dielectric material. The feed assembly (26) operates within the Ku-band frequency range to yield high gain, collimated, independent first and second beams (32, 36). The feed assembly (26) can be implemented in a tropospheric scatter communication system (38) in conjunction with a reflector (22) to provide concurrent transmit and receive capability via the two independent, angularly separated first and second beams (32, 36).

Abstract: A system and method for capacity analysis in communication networks, particularly for on the move ad hoc wireless packet-switched networks, as well as wide variety of other multimedia networks. The invention seeks to use the same two attributes per link (link capacity and link utilization) as known circuit-switched based analysis tools while incorporating useful aspects of various statistical analyses, such as a Queuing Theory based analysis, among others. In one embodiment, the invention introduces four tests to be implemented per each link, with results of these four tests being used to color code link congestion states to generate the reports for a planner. These four tests may generate an improved analysis of the network utilizing the same number of variables used in simple conventional circuit switched based analysis.

Abstract: An RF receiver (12) includes a channel estimator (52). The channel estimator (52) includes a channel estimation filter (82), error signal generator (84), and normalized Least-Mean-Square (NLMS) filter-definition generator 86. The filter (82), error generator (84) and NLMS filter-definition generator (86) function together as an adaptive estimator. An error signal (90) is formed with a received signal (48). The filter (82) filters an estimated transmit signal (74) constructed from lower confidence decision data (66) and higher confidence known preamble data (30?). An adaptive filter definition (94) is formed in a feedback, loop which minimizes correlation between the estimated transmit signal (74) and the error signal (90). A convergence signal (122) is modulated in synchronism with the changes between lower and higher confidence data in the estimated transmit signal (74).

Abstract: Systems and methods are provided for signaling control information in a communication of data. The method includes overwriting a portion of a frame in a sequence of frames with control information. The control information has a low bit size, and the overwriting is performed at a frequency of less than about 20% of the frames. The system includes a spread spectrum transmitter that includes a channel coder, an interleaver and framer unit, and an insertion unit. The insertion unit is configured to overwrite a portion of a frame in a sequence of frames with control information and is further configured to overwrite at a frequency of less than about 20% of the frames.

Abstract: A wireless network (100) includes a number of definable radio systems (102) in communication with one another via a wideband backbone (108). Each of the systems (102) includes a first software programmable transceiver (200) for extra-network communication using a narrowband channel defined by a radio frequency capability (106). Each of the radios (102) further includes a second transceiver for intra-network communication using wideband backbone (108). Methods for operating the network (100) enable the radios (102) to engage in communication over narrowband channels to carry a signal between multiple radios (102) and an extra-network location, and for communicating the signal as distinct bitstreams between the radios (102) and another of the radios (102) using the wideband backbone (108).

Abstract: Apparatus are provided for a communication signal processing apparatus having a channel estimator configured to generate a first channel estimation at a first time point, a linear predictor coupled to the channel estimator, and an adaptive filter coupled with the linear predictor. The linear predictor is configured to predict a second channel estimation based on a second time point and a channel frequency. The second time point is concurrent or subsequent to the first time point. The second channel estimation includes a first coefficient. The linear predictor includes a first predictor having a sample time point. The first predictor is configured to generate the first coefficient of the second channel estimation based on the sample time point and the second time point. The sample time point is prior to the second time point. The adaptive filter is configured to recursively determine the second channel estimation.

Abstract: A programmable modem (20) for processing a waveform includes a general purpose processor (GPP) engine (34) and special purpose programmable signal processing engines (22) in communication with the GPP engine (34). Each of the special purpose engines (22) executes a special purpose software program (80) to process a portion of the waveform under one of a plurality of communications standards in response to control signals from the GPP engine (34). A power manager engine (56) is in communication with the GPP engine (34) and the signal processing engines (22). The power manager engine (56) responds to the control signals from the GPP engine (34) to power currently used ones of the special purpose engines (22) and to discontinue power to unused ones of the special purpose engines (22). The programmable modem is implemented on a single CMOS integrated circuit (66).

Abstract: A symbol synchronizer (100) is provided for a software-defined communications system (10). The symbol synchronizer (100), when integrated into either a pre- or post-detection diversity signal combiner (108, 208), enables highly accurate signal synchronization with minimal added system complexity. The symbol synchronizer (100) includes a single complex sliding window-matched filter (102) for filtering an input digital signal with a match filtering function based on predetermined signal transfer function characteristics to average out receiver noise from the signal. A signal delay bank (84) includes a plurality of delay blocks each for delaying the digital signal filtered by the single matched filter for a predetermined number of samples. A complex correlator (88) correlates the digital signal filtered by the single complex sliding window matched filter (102) and delayed by the complex correlator (88) with a correlator reference signal, and selects an index of a path having a peak correlator value.

Abstract: An embodiment of a method for parameterizing an input signal includes non-linearly transforming the input signal, removing higher order terms by passing the input signal through a low pass filter to produce a linear combination of data symbols and DC components, solving for the DC components, separating a plurality of mixed baseband signals from the input signal, and coordinate transforming each of the separated signals from polar coordinates to Cartesian coordinates. An embodiment of a receiver includes a non-linear transform operator receiving a digitized input signal and adapted to produce a linear combination of data symbols, DC components, and carrier effects; a low-pass filter for removing higher order terms; a separator unit for separating the plurality of mixed baseband signals; and a coordinate transform for converting the separated signals from polar coordinates to Cartesian coordinates.

Abstract: A feed assembly (26) for an antenna system (38) includes a first feed element (30) that propagates a first beam (32) and a second feed element (34) that propagates a second beam (36). The second feed element (34) is collocated with, but displaced vertically from, the first feed element (30) to achieve angular diversity in elevation. Each of the feed elements (30, 34) has an elongated conical shape and is formed from a dielectric material. The feed assembly (26) operates within the Ku-band frequency range to yield high gain, collimated, independent first and second beams (32, 34). The feed assembly (26) can be implemented in a tropospheric scatter communication system (38) in conjunction with a reflector (22) to provide concurrent transmit and receive capability via the two independent, angularly separated first and second beams (32, 36).

Abstract: A multi-carrier communication system (400) groups subchannels (802) into different quality-of-signal (QoS) regions (804). An unconstrained optimization process (1200) is performed independently for the subchannels (802) of the different QoS regions (804) to allocate bit rates and power to the individual subchannels (802) so that the indicated QoS will result. Coders (504, 508, 512, 516, 1700) partition and error-correction encode source information using encoding schemes matched to the different QoS regions (804). A set (1100) of only a few directed QoS partition vectors (1102) direct the unconstrained optimization process (1200) to attempt bit-rate and power allocations on only a few promising groupings of subchannels (802) and QoS regions (804). An iterative process may take place between bit-rate and power allocation on one side and source information coding on the other for different directed QoS partition vectors (1102) to identify the best solution.

Abstract: A system (100) and method for the reception and despreading of a code-division multiple access (CDMA) global positioning system (GPS) signal (200), or other direct-sequence spread-spectrum (DSSS) signals, is provided. An antenna array (102) receives the DSSS signal (200) over a plurality of elements (116). A preprocessor (104) down converts and digitizes the DSSS signal (200) to produce a signal stream (202) in the time domain. An FFT (106) transforms the signal stream (202) to the frequency domain. A beam former (108) generates a reception beam (201) for the DSSS signal (200) in the frequency domain, and also implements a narrowband frequency notch, if desired. A despreader (110) despreads the transformed signal stream (204) in the frequency domain. An IFFT (112) transforms the despread signal stream (208) back to the time domain. And a postprocessor (114) converts the transformed despread signal stream (210) into a desired received signal stream (212) in the time domain.

Abstract: A multi-carrier communication system (400) groups subchannels (802) into different quality-of-signal (QoS) regions (804). An unconstrained optimization process (1200) is performed independently for the subchannels (802) of the different QoS regions (804) to allocate bit rates and power to the individual subchannels (802) so that the indicated QoS will result. Coders (504, 508, 512, 516) partition and error-correction encode source information using encoding schemes matched to the different QoS regions (804). A set (1100) of only a few directed QoS partition vectors (1102) direct the unconstrained optimization process (1200) to attempt bit-rate and power allocations on only a few promising groupings of subchannels (802) and QoS regions (804). An iterative process may take place between bit-rate and power allocation on one side and source information coding on the other for different directed QoS partition vectors (1102) to identify the best solution.

Abstract: A robust and flexible system for signal parameter measurements in the field of signal processing dynamically uses signal parameters from previous signal detections and parametric priorities to adaptively control and process the signal in an efficient and reliable manner. The system provides for improved fine grain signal parameter measurements through the use of adaptive arbitration to control signal processing. The system improves measurement accuracy for various signal characteristics including pulse width, amplitude, frequency and timing information. The system also provides signal parameter measurements while requiring less power, size, and weight than conventional systems.

Abstract: A method and system is disclosed for cross-correlating information between the domains of network management and network security. The present invention discloses a model representing the security domain that can be used to define relationship between devices and events in the security domain in the context of a managed network. With this model, a security topology of the network security domain can be created based on the current implementation of the network. This model and topology allows the present invention to correlate relevant network security information to diagnose problems as they occur by using events detected within the network. Using the disclosed method and system for correlating information in the network security, the present invention provides further enhancements over conventional methods by cross-correlating information between the network security and network management domains to aid in their detection and analysis of problems.

Abstract: A method and apparatus for adaptive signal compression of unknown signals uses minimal power and bandwidth to transmit data. The method provides adaptive signal compression with minimal loss and distortion by extracting only information of interest and recreating the full signal. The method uses a single resolution filter bank for channelizing a data stream for transmission. The method removes unwanted or unneeded information before transmitting the data by using fidelity and user controls and detection capabilities. The method provides significant signal compression where signals are sparse in frequency, time, or both and does not rely on a priori knowledge of the signal. After transmission, the system generates a signal using the data received as well as filling in the non-transmitted portions of the signal by manipulating the transmitted data. The system then formats the signal into the original data stream using a reconstruction filter bank.

Abstract: An analog-to-digital converter (“ADC”) architecture as described herein utilizes a digital signal processor having suitably configured waveform prediction logic that can predict expected types of input signals. The ADC architecture subtracts the predictable signal components from the analog input signal prior to the analog-to-digital conversion, which extends the dynamic range of the ADC employed by the ADC architecture. In practice, the ADC architecture can subtract predictable strong signal components from an analog input signal such that the ADC can apply its available dynamic range to the remaining weak signal components.