Abstract: A communication system is provided that includes a transmitter device and a receiver device. The transmitter device transmits input data as a transmitted signal having the known non-linear distortion (NLD) characteristic. The receiver receives a received signal that represents a channel affected version of the transmitted signal and that has the known NLD characteristic. The received signal includes power amplifier distortion (PAD) induced by the transmitter device's power amplifier. The receiver is designed to iteratively estimate, based on the known NLD characteristic, remaining PAD caused by the power amplifier, and to iteratively cancel estimated PAD to reduce PAD in the received signal.

Abstract: Embodiments include methods and apparatus for performing symbol timing synchronization for a symbol-bearing signal. The symbol-bearing signal is sampled to produce a plurality of symbol samples. First-direction interpolation processes are performed on the plurality of symbol samples in a first temporal direction, where the first temporal direction is a direction from a first sampling time towards a second sampling time. In addition, second-direction interpolation processes are performed on the symbol samples in a second temporal direction, where the second temporal direction is a direction from the second sampling time towards the first sampling time, resulting in a set of interpolated symbol samples.

Abstract: In a wireless ad hoc network (20) of nodes (22), a method (64) of power management entails monitoring (82) a current traffic load of the network (20), and in response to the current traffic load, selecting (106, 132) a subset (102) of epochs (80) within cyclically repeating time windows (78) for network communication. A message (122) is communicated (120) between the nodes (22) in the network (20). The message (122) identifies the subset (102) of epochs (80) for using in communicating network traffic (32). Following receipt of the message, each of the nodes (22) modifies (124) a transmit capability mode by entering a run state (40) during the epochs (80) within the subset (102) to enable communication of network traffic (32) and by entering a low power consumption idle state (42) during the remaining epochs (80) within the time window (78).

Abstract: Systems and methods are described for efficiently transmitting packetized data from a sender to a receiver over a communications link. A compression context is established between the sender and the receiver based upon commonalities in each of the data packets prior to transmitting the data over the communications link. The data is compressed according to the compression context to thereby create compressed data packets, and the compressed data packets are transmitted to the receiver across the communications link. By establishing compression contexts prior to transmission, the need for in-band signaling is reduced or eliminated.

Abstract: A processing system (60) includes an input interface (62), a first processor (64), a second processor (66), and an output interface (68) arranged in a serial configuration. Each of the input interface (62), first processor (64), second processor (66), and output interface (68) computes a digest (92, 100, 110, and 114) using information, e.g., a unique parameter (94, 102, 112, 118), known only by that element (62, 64, 66, 68) and using information generated by that element (62, 64, 66, 68). The digests (92, 100, 110, and 114) are used to validate the integrity of payload data (86) processed by the system (60) to form processed data (104) and the system (60) only outputs the processed data (104) upon validation of data integrity. The serial configuration of system (60) may be implemented to provide high bit rate, redundant cryptographic services.

Abstract: Embodiments include methods for determining synchronization/pilot sequences (SPS) to be utilized in conjunction with transmissions by antennas of a multiple-antenna transmitter. The SPS include pilot signals that are positioned at subcarriers that are orthogonal in frequency with subcarriers at which pilot signals of other antennas are positioned. The pilot signals may be unevenly spaced across the in-band subcarriers. The multiple-antenna transmit system generates a plurality of wireless signals, each of which may include an SPS having synchronization information in a first plurality of in-band subcarriers and the pilot signals in a second plurality of in-band subcarriers. The wireless signals are simultaneously radiated over a wireless communication channel using a different antenna. A receiver receives channel-affected versions of the wireless signals, and produces a corrected signal by applying corrections to the received signal based on estimated channel perturbations within the received signal.

Abstract: An embodiment includes a method for generating a set of synchronization/pilot sequences (SPS) by generating a plurality of candidate SPS using different initial conditions. Correlations are performed among the candidate SPS to generate a plurality of correlation values, and a plurality of permutations of the candidate SPS are determined, where each permutation includes a different set of candidate SPS, and wherein each permutation includes a number, D, of candidate SPS. In addition a selected permutation is identified from the plurality of permutations, where the selected permutation corresponds to the set of SPS being generated. A system includes a transmitter adapted to generate a wireless signal in which an SPS is embedded by combining each SPS of the set with phase shifted input data, determining peak-to-average power ratios (PARs) for at least some of the combined signals, and identifying a selected combined signal based on the PARs.

Abstract: A method and system are provided for reducing power amplifier induced distortion. Power amplifier induced distortion is iteratively estimated and cancelled. When the difference between the current estimated power amplifier distortion and the previous estimated power amplifier distortion is less than a convergence threshold, particular M-QAM constellation points that are still in error are determined A M-QAM constellation point correction routine is provided that can move the incorrectly estimated M-QAM constellation points that are in error towards their expected quadrants by generating updated M-QAM constellation points. The remaining estimated non-linear power amplifier induced distortion in the received signal can then be estimated and canceled.

Abstract: Embodiments of methods and apparatus for wirelessly communicating signals include one or more transmitters configured to generate a plurality of wireless signal for transmission. Each of the wireless signals includes a plurality of pilot signals represented in a plurality of unevenly spaced, in-band subcarriers. Pilot signals of each wireless signal are positioned at subcarriers that are orthogonal in frequency with subcarriers at which pilot signals of all other wireless signals are positioned. According to an embodiment, subcarrier indices each the plurality of pilot signals are determined using a third order or higher order polynomial parameterization of pilot subcarriers in conjunction with a convex optimization algorithm to produce pilot signals having near-optimal channel estimate mean square error (MSE) performance. The wireless signals are simultaneously radiated over a wireless communication channel using a plurality of co-located or distributed antennas.

Abstract: An embodiment for wirelessly communicating a signal includes a transmitter combining a plurality of phase shifted input data signals with a plurality of synchronization/pilot sequences to produce a plurality of combined signals, performing frequency domain-to-time domain transformations of the combined signals to produce a plurality of candidate signals, determining peak-to-average ratios for at least some of the plurality of candidate signals, identifying a selected signal from the plurality of candidate signals based on the peak-to-average ratios, and transmitting the selected signal over a wireless communication channel.

Abstract: An embodiment of a method for communicating call control signaling information in a communications system that includes a user equipment (UE) and a base includes the UE formatting the call control signaling information, transmitting the call control signaling information over a first logical channel that is mapped to a first transport channel, and transmitting user traffic over a second logical channel that is mapped to a second transport channel. In an embodiment, the base receives the call control signaling information from the UE over the first logical channel, receives the user traffic from the UE over the second logical channel, and transmits the call control signaling information to a core network. In an embodiment, the communication system is an IP network in which information is exchanged between the UE and the base using a W-CDMA transmission protocol. The base may form a portion of a satellite-based radio network.

Abstract: Systems and methods efficiently process digests, hashes or other results by performing multiplicative functions in parallel with each other. In various embodiments, successive processing stages are provided, with each stage performing parallel multiplicative functions and also combining input terms to reduce the total number of terms that remain to be processed. By progressively combining the active terms into a smaller number of terms for subsequent processing, the time needed to process a result can be significantly reduced.

Abstract: A wireless network (20) with at least a first radio communication unit (24) and a second radio communication unit (26) transmits and receives signals with minimal interference from the surrounding environment of the first unit (24) and second unit (26). The first radio communication unit (24) determines frequencies (54) having power level above a threshold (52), and creates a list of these frequencies (50) to be transmitted to the second radio communication unit (26). The second radio communication unit (26) places notches (140) in its transmission band (88) based on frequencies (54) in the list (50), reserved frequencies (132), and local frequencies (92) having signal energy above a threshold (90). When transmitting a signal (42), the second radio communication unit (26) avoids transmitting in frequencies that have notches (140).

Abstract: A method (104), operable on a processor platform (24), and a code module (38) facilitate navigation between webpages (34) of a website (32). The code module (38) is incorporated into the webpages (34), and is executed at the processor platform (24) when one of the webpages (34) is downloaded to the processor platform (24). Upon execution of the code module (38), a destination address (36) for the downloaded webpage (34) is obtained. When one or more keywords are detected in the destination address (36), a thread of navigation links (124) related to the keywords is generated and displayed within the current website. The navigation links (124) reference other webpages (34) of the website (32) pertinent to the current webpage (34), and these other webpages (34) can be downloaded when their associated navigation links (124) are activated.

Abstract: A method for reliable computation of point additions and point multiplications in an elliptic curve cryptography (ECC) system. Two asymmetric operations are performed: one of the operations is of slightly higher complexity than a conventional ECC operation, and the other operation is of much lower complexity than the first operation. The complexity of the second operation is a function of the desired degree of reliability, or the desired probability of failure detection.

Abstract: In an embodiment, a receiver includes an antenna configured to receive a communication frame. The communication frame may include an acquisition code symbol sequence, which in turn may include a plurality of acquisition code symbols. In an embodiment, an acquisition code symbol includes a subcode sequence having a plurality of subcodes. A receiver also may include a correlation calculator coupled to the antenna. The correlation calculator may be configured to determine a correlation between the subcodes of the received communication frame and a stored version of the subcodes. The correlation may be used in determining a timing offset for further processing of the communication frame.

Abstract: An embodiment for wirelessly communicating a signal includes a transmitter combining a plurality of phase shifted input data signals with a plurality of synchronization/pilot sequences to produce a plurality of combined signals, performing frequency domain-to-time domain transformations of the combined signals to produce a plurality of candidate signals, determining peak-to-average ratios for at least some of the plurality of candidate signals, identifying a selected signal from the plurality of candidate signals based on the peak-to-average ratios, and transmitting the selected signal over a wireless communication channel.

Abstract: A communications system (20) includes a resource controller (22) and a terminal (24) in communication with the resource controller (22). Periodically, the resource controller (22) sends a service announcement (46) that identifies a set (50) of timeslots (52) within a communication resource (40) configured for random access within a future frame (42). The terminal (24) ascertains a burst characteristic (118) of a message (54) to be sent from the terminal (24) and generates a random access parameter (128). The terminal (24) selects one of the timeslots (52) from the set (50) in accordance with the random access parameter (128), the timeslot exhibiting a burst type (62) corresponding to the burst characteristic (118) of the message (54). The terminal (24) transmits the message (54) in the selected timeslot (52).

Abstract: An embodiment for wirelessly communicating a signal includes a transmitter generating and transmitting a wireless signal over a wireless communication channel. The wireless signal includes a guard band, data represented within a plurality of data-bearing subcarriers, and a plurality of pilot signals represented within a plurality of pilot subcarriers. In an embodiment, the plurality of pilot signals have variable pilot signal parameters selected from a group of parameters that includes pilot power and pilot spacing with respect to adjacent pilots. An embodiment further includes a receiver receiving a channel-affected version of the wireless signal, and producing a corrected signal by applying corrections to the received signal based on estimated channel perturbations within the received signal, where the estimated channel perturbations are determined based on the plurality of pilot signals. The receiver also produces an output data symbol from the corrected signal.

Abstract: A cryptographic system (100) and methodology executable within the cryptographic system (100) enable the use of a programmable logic device PLD (108) in a single chip cryptographic design flow for secure cryptographic services. Methodology for secure configuration of the PLD (108) within a cryptographic system 100 entails secure configuration and authentication (202), functional verification (204), configuration key reload capability (206), traffic key load capability (208) using a split key technique, isolation between command and key fill domains for secure key fill (210) of key material, redundant system instantiation (212), and high speed comparison for secure operation.