Wichita State University

Neoreach, Inc.

United States of America As Represented by the Secretary of the Air Force

Motorola Corporation

The University of Alabama

Cubit De, LLC

Hyuck M Kwon

Khanh D Pham

Yoo S Song

Clinton C Powell, Ii

Yang-Ki Hong

Edward K Lee

Vidhi Rana

Matthew R Hannon

Weiguang Hou

David Hastings

Chandana K K Jayasooriya

Kyung Y Min

Tatcha Chulajata

Ryan Syslo

Bing Wang

Madhuprana Goswami

Jie Yang

Kyung M Min

Krittetash Pinoyoanuntapong

Bing H Wang

A satellite communications system is disclosed, the system comprising a ground controller, a decode-and-forward (DF) satellite transponder, and a digital high-power amplifier (HPA). The DF is further comprised of a transponder front end including a digital channelizer and a predistorter. The ground controller is configured to transmit multiple-access frequency-division-multiplexed signals to the DF, where the DF is configured to down-convert the signals received at the transponder front end. The digital channelizer is configured to convert the signals received into a single sample steam and feed the stream through the predistorter into the single digital HPA, wherein the HPA is configured to amplify each input sample of the stream in sample-by-sample fashion and generates a discrete output. The DF is further configured to convert the output of the digital HPA to a continuous time signal and up-convert the output with a main carrier frequency for down-link transmission to multiple-access ground users.

Digital channelizer with predistorter, high-power amplifier, and beamforming

The present disclosure provides an anti jamming system for a wireless communication system an antenna array comprising N antenna elements. At least two multiphase filters being connected to the antenna array and configured to receive an antenna element signal from each one of the N antenna elements. An anti-jamming system for a wireless communication system comprising an antenna array comprising N antenna elements and a filter configured to attenuate jamming signals from sources that is greater than, less than, or equal to N. An anti-jamming system for a wireless communication system comprising a multiphase filter connected to the antenna array to receive an antenna element signal from each antenna element of the antenna array, the multiphase filters comprising a first phase and a second phase, wherein the first phase of the multiphase filter executes a Frost's algorithm and the second phase of the multiphase filter executes a Maximin algorithm.

Anti-jamming system

Fully connected uplink and downlink fully connected relay network systems using pseudo-noise spreading and despreading sequences subjected to maximizing the signal-to-interference-plus-noise ratio. The relay network systems comprise one or more transmitting units, relays, and receiving units connected via a communication network. The transmitting units, relays, and receiving units each may include a computer for performing the methods and steps described herein and transceivers for transmitting and/or receiving signals. The computer encodes and/or decodes communication signals via optimum adaptive PN sequences found by employing Cholesky decompositions and singular value decompositions (SVD). The PN sequences employ channel state information (CSI) to more effectively and more securely computing the optimal sequences.

Spreading sequence system for full connectivity relay network

A system and method for generating a channel statistics dependent frequency hopping pattern that requires low computational complexity and simultaneously maximizes channel capacity and minimizes the symbol error rate or bit error rate under partial band tone interference and Rician or other fading environments. The system includes one or more transmitting units and one or more receiving units communicating over a wireless communication network. A signal generated at one of the transmitting units is modified via the channel statistics dependent frequency hopping pattern as generated via one of the receiving units for improved signal accuracy and avoiding interferer detection and/or interference hits.

System and method for channel probability mass function dependent frequency hopping

A system and method for transmitting data over a wireless communication network. The method broadly includes generating a frequency hopping pattern spanning a plurality of time hops and a plurality of signal frequencies; generating a signal including a number of data symbols, the signal incorporating the frequency hopping pattern such that the symbols are distributed across the signal frequencies according to the frequency hopping pattern; transmitting the signal from a transmitting unit to a receiving unit over the wireless communication network; and generating an exact symbol error rate for the signal as received by the receiving unit.

System and method for generating exact symbol error rates of frequency-hopped signals

A MIMO antenna for mobile devices has a system board, and two or more microstrip lines extending along a top surface of the system board. The MIMO antenna additionally includes a ground plane extending along a bottom surface of the system board, wherein the ground plane has a Y-shaped slot. The MIMO antenna further includes one or more pairs of miniature antenna elements attached to the top surface of system board in contact with the at least two microstrip lines, wherein the antenna elements are slanted at &#xb1;45&#xb0; with respect to a center Z of an X Y coordinate system, and center of a radiation sphere, located proximate the Y-shaped slot.

Hexaferrite slant and slot MIMO antenna element

A pseudonoise code teaching loop (PNCTL) measures the difference in energy between a smart antenna array output that is despread using an early pseudonoise code and a late pseudonoise code and contains a chip time shifting current based on this difference. Using multiple elements of the array significantly improves performance.

PN code chip time tracking with smart antenna

Recently, a smart antenna, i.e., a blind adaptive antenna array, has attracted much attention to suppress multiple access interference (MAI) and multipath signals to improve the capacity of a code division multiple access (CDMA) wireless communications system. Most of the smart antenna algorithms either need matrix computation or complex calculations. In this invented direction-of-arrival (DOA) tracking algorithm only 2M complex multiplications are required per snapshot. Further more the DOA tracking algorithm is not sensitive to the mixer phase distortions. Hence the system complexity is reduced since a separate phase calibration is not required for the DOA tracking algorithm. Also the equivalent DOA tracking error due to the mixer phase distortions is derived. Simulation results show that the DOA tracking algorithm in the present invention works effectively under additive white Gaussian (AWGN) as well as Rayleigh fading environments. Also the system employing the invented smart antenna has the same bit error rate (BER) performance as those of other existing smart antennas, however, has less computation burdens and complexity.

Direction of arrival angle tracking algorithm for smart antennas

A cellular architecture includes antenna arrays that are arranged to reduce soft handoff areas, thereby increasing system performance. The arrays are arranged such that each of the arrays are aligned along one of a plurality of parallel lines in a first direction at a regularly spaced interval, each of the arrays on a single line in the first direction having a same orientation, each of the arrays along adjacent parallel lines being staggered with respect to a nearest neighboring array in a second direction such that the second direction forms an angle of approximately 10.89 degrees with respect to a direction perpendicular to the first direction. In preferred embodiments, the orientation of arrays along adjacent parallel lines is rotated by sixty degrees with respect to each other. The architecture is particularly well-suited to CDMA systems. In preferred embodiments including smart antenna arrays, transmission to mobile users occurs along a primary multipath and two secondary multipaths. A method for determining performance of cellular systems by calculating the asymptotic capacity is also provided.

Methods for making a cellular system, transmitting to a mobile user in a cellular system, and evaluating the performance of a cellular system

The present invention describes an inexpensive as well as efficient smart antenna processor for a code division multiple access (CDMA) wireless communications system, such as a 3 generation (3G) CDMA2000 or W-CDMA system. Separate channel estimation is not required in the present invention, in contrast to a CDMA system with a conventional smart antenna. In addition, the phase distortions due to the different radio frequency (RF) mixers can be automatically compensated in the present invention. Thus, separate phase calibration is not necessary for a smart antenna processor according to the present invention, if the reverse link demodulation is concerned. Furthermore, bit error rate (BER) performance of a CDMA system with the adaptive algorithm in the present invention can be smaller than that of a conventional algorithm, for fading and additive white Gaussian noise (AWGN) environments.

Smart antenna with no phase calibration for CDMA reverse link

A pseudonise (PN) code acquisition scheme employs all elements of a smart antenna array and an adaptive threshold. The basic structure is the combination of a conventional PN correlation searcher, an adaptive beamformer, and an adaptive threshold setting circuit. During each observation interval, the adaptive beamformer adaptively updates the weight vector for the smart antenna elements using the accumulated received signal despread with trial PN code phase error as input, preferably at the chip rate. A spatially correlated signal is then formed by weighting an accumulated value of the signal received by each antenna in the array over the observation period with the corresponding final weight of smart antenna weight vector as calculated by the adaptive beamformer. This spatially correlated signal is then compared to a threshold to determine whether PN code acquisition has occurred. In preferred embodiments, an adaptive threshold setting algorithm is employed to adapt to varying environment for efficient PN code acquisition. The adaptive threshold setting circuit accumulates the signal received by each element over the observation period, multiplies the accumulated values by the updated weight vector and combines the weighted values to an average estimated power. The average estimated power is then employed to scale a fixed reference threshold to create the adaptive threshold.

PN code acquisition with adaptive antenna array and adaptive threshold for CDMA wireless communications

A smart antenna, i.e., blind adaptive antenna array, is a method and system to suppress multiple access interference and to improve performance, for example in a code division multiple access (CDMA) wireless communications system, including third generation (3 g) cdma2000 and wide band (W)-CDMA. A convergence parameter is employed in a smart antenna processor. In general, a constant convergence parameter value is empirically determined and used after studying the convergence speed and the steady state mean square error (MSE) or other performance data, such as bit error rate. As the convergence parameter value increases, the convergence speed also increases but the MSE increases unfortunately, and vice versa. The traditional smart antenna with a constant convergence parameter would yield poor performance when the channel environment changes, which is true particularly when a mobile user moves around. In the present invention, the convergence parameter value is adaptively changed and employed in a smart antenna processor. Two exemplary methods to update the convergence parameter are described. By employing such an adaptive convergence parameter value, convergence speed can be increased and the steady state MSE can be decreased.

Smart antenna with adaptive convergence parameter

A communication device with a synchronized zero-crossing demodulator is described. A synchronizer system (123, 223, 125, 227) and method derives symbol transition timing information from a zero-crossing detector output. The synchronizer (123, 223) is, in one embodiment, connected to the output of a zero-crossing detector (120, 220), to provide an edge clock signal to a phase angle estimator (122, 226), which is passed to a decision device 124, which provides a symbol estimate which is later decoded into an information message. In an alternative embodiment, a synchronizer is combined with the phase angle estimator (125, 227) to provide as an output, a phase angle estimate which is passed to a decision device (124) which provides a symbol estimate signal (127, 229), which is later decoded to obtain the information message. The alternative embodiment allows recovery of the second symbol which is typically lost in implementing the first embodiment of the system, to avoid second order error effects on recovered data.

Growing community of inventors

Wichita, KS, United States of America

Hyuck M Kwon