Patents by Inventor Donald C. D. Chang

Donald C. D. Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20180109689
    Abstract: An apparatus comprises a segmenter and a pre-processor. The segmenter segments a first stream of data into P-1 substreams, P being an integer greater than 1. The pre-processor, having N input ports, N being an integer greater than P-1, receives the P-1 substreams at P-1 ports of the N input ports and a second stream at a Pth input port. The pre-processor generates P output streams from the P-1 substreams and the second stream using a P-to-P K-muxing operation. The P output streams are uploaded to a cloud storage via a network. Redundancy of the P output streams recovered by a user from the cloud storage is based on whether the second stream is accessible to the user.
    Type: Application
    Filed: December 18, 2017
    Publication date: April 19, 2018
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Steve K. Chen
  • Publication number: 20180102832
    Abstract: A system includes a ground hub and a mobile airborne platform hovering over or close to a coverage area on or near the earth surface. The mobile airborne platform comprises a bistatic radar receiver including an antenna system to capture first radiofrequency signals originated from a first satellite and second radiofrequency signals originated from a second satellite, via direct paths and via reflected paths from the coverage area. The mobile airborne platform transmits the captured first and second radiofrequency signals to a ground hub via a feeder link. The ground hub includes a remote beam forming network to remotely form receiving beams for the antenna system of the bistatic radar receiver to capture the first and second radiofrequency signals, and a remote radar processing center to transform the captured first and second radiofrequency signals into a first and a second two-dimensional radiofrequency image, respectively.
    Type: Application
    Filed: October 17, 2017
    Publication date: April 12, 2018
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Patent number: 9935647
    Abstract: A broadband digital beam forming system comprises a set of Q pre-processing modules, Q being an integer greater than or equal to 2, and a set of M digital beam forming modules in communication with the Q preprocessing modules. Each of the Q preprocessing modules receives a respective one of Q broadband input signal streams and outputs M narrowband signal streams, M being an integer greater than or equal to 2. The total number of narrowband signal streams outputted by the Q pre-processing modules is Q times M. Each of the M digital beam forming modules receives corresponding Q narrowband signal streams of the Q times M narrowband signal streams, and outputs R beam signals, R being an integer greater than or equal to 1. The system further comprises a set of R post-processing modules in communication with the M digital beam forming modules.
    Type: Grant
    Filed: November 13, 2016
    Date of Patent: April 3, 2018
    Assignee: Spatial Digital Systems, Inc.
    Inventor: Donald C. D. Chang
  • Publication number: 20180081067
    Abstract: A method and a system for reducing undesired interference in a target zone. A set of M pickup sensors pick up undesired signals in real time and generate M pickup signals, M being an integer greater than or equal to 1. A beam forming network coupled to the M pickup sensors comprises a receiving beam forming module and a transmitting beam forming module. The receiving beam forming module receives the M pickup signals and generates K beam signals, K being an integer greater than or equal to 1. The transmitting beam forming module receives the K beam signals and generates N interference signals, N being an integer greater than 1. A set of N injectors coupled to the transmitting beam forming module receives the N interference signals, respectively, and radiates the N interference signals to the target zone.
    Type: Application
    Filed: November 28, 2017
    Publication date: March 22, 2018
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: DONALD C. D. CHANG, MICHAEL T. H. LIN, STEVE CHEN
  • Patent number: 9917719
    Abstract: A satellite broadcasting system is achieved where remote beam forming processors combined with wavefront multiplexers located among distributed ground stations are used to control downlink beam footprints and pointing directions. Digital beam forming (DBF) techniques allow a single satellite download broadcast antenna array to generate multiple independently pointed simultaneous downlinks, which may contain distinct information content. Allocation of some uplink back-channel elements as diagnostic signals allows for continuous calibration of uplink channels, improving downlink broadcast array and user broadcast performance. Wavefront multiplexing/demultiplexing allows all array element signals to be radiated by the broadcasting antenna array, with simultaneous propagation from ground stations to the broadcasting satellites through available parallel propagation channels in the uplinks of feeder links, with equalized amplitude and phase differentials.
    Type: Grant
    Filed: July 21, 2014
    Date of Patent: March 13, 2018
    Assignee: Spatial Digital Systems, Inc.
    Inventor: Donald C. D. Chang
  • Patent number: 9917635
    Abstract: Signals of data streams for transmission to user equipment (UE) in spoke-and-hub configurations will utilize multiple transponders of satellites. Radiation patterns from ground terminals with distributed apertures feature orthogonal beams (OB). A tracking OB beam from a moving platform dynamically shall autonomously be formed as a shaped beam by a digital-beam-forming (DBF) network with a peak to a desired satellite, and nulls to undesired satellites to minimize mutual interferences among multiple satellite spatially. Ground hubs and mobile terminals feature “coherent” bandwidth aggregating capability from multiple available but non-contiguous slices of frequency slots in many transponders by wavefront multiplexing/demultiplexing (WF muxing/demuxing) techniques. These individual frequency slots must be dynamically selected, calibrated and equalized continuously in receivers via embedded probing signals as a part of WF muxing/demuxing techniques.
    Type: Grant
    Filed: March 10, 2014
    Date of Patent: March 13, 2018
    Assignee: Spatial Digital Systems, Inc.
    Inventor: Donald C. D. Chang
  • Publication number: 20180048371
    Abstract: A communication system includes a transmitter, one or more active scattering platforms, and one or more remote receivers. The transmitter includes a beam forming network for transforming M signals into a set of shaped beams which are radiated toward the active scattering platforms by transmitter antenna elements. The active scattering platforms receive and re-radiate one or more of the radiated shaped beams toward the receivers. The beam forming network optimizes composite transfer functions under performance constraints. Each composite transfer function is a linear combination of transfer functions. Each transfer function characterizes propagation paths from one transmitter antenna element to one receiving antenna element. Each receiving antenna element is identified by a user element identification index in the transfer functions. Each receiver is identified by a user identification index.
    Type: Application
    Filed: October 3, 2017
    Publication date: February 15, 2018
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee
  • Patent number: 9882641
    Abstract: A data communication system comprises a central office processor which comprises a first input mapping unit, a first wave-front multiplexer, and a first output mapping unit. The first input mapping unit receives and dynamically maps digital data into a plurality of first electronic signals. The first wave-front multiplexer is coupled to the first input mapping unit to receive the first electronic signals, perform a wave-front multiplexing transformation on the first electronic signals, and output wave-front multiplexed signals, each of the wave-front multiplexed signals being a linear combination of the first electronic signals. The first output mapping unit is coupled to the first wave-front multiplexer to receive and dynamically map the wave-front multiplexed signals into second electronic signals.
    Type: Grant
    Filed: July 17, 2017
    Date of Patent: January 30, 2018
    Assignee: Spatial Digital Systems, Inc.
    Inventor: Donald C. D. Chang
  • Patent number: 9866300
    Abstract: Four independent technologies are incorporated in this invention to efficiently and cost effectively implement dynamic last mile connectivity. The four technologies are passive optical networks (PON), Small cell, wavefront multiplexing (or K-muxing), and digital beam forming (DBF). We have filed US patents for communications architectures featuring K-muxing overlaid over low cost of PON. Those inventions relate particularly to resource allocation in passive optical networks (PON) via wavefront multiplexing (WF-muxing or K-muxing) and wavefront demultiplexing (WF-demuxing or K-demuxing). The “WF-muxing in PON” can be configured for performing remote digital beam forming (RDBF) over a service area covered by multiple small cells. The RDBF may generate multiple shaped beams with enhanced connectivity and better isolations over a same frequency slot concurrently to serve multiple users over the coverage area.
    Type: Grant
    Filed: January 12, 2016
    Date of Patent: January 9, 2018
    Assignee: Spatial Digital Systems, Inc.
    Inventors: Donald C. D. Chang, Juo-Yu Lee, Steve K. Chen
  • Patent number: 9866226
    Abstract: An analog-to-digital conversion system includes a first processor, a bank of N analog-to-digital converters, and a second processor. The first processor receives M input signal streams, performs a wave-front multiplexing transform that includes a first set of wave-front vectors on the M input signal streams in analog domain and outputs concurrently N mixed signal streams, M and N being integers and N?M>1. The N analog-to-digital converters convert the N mixed signal streams from analog format to digital format and output concurrently N digital data streams. The second processor receives the N digital data streams, performs a wave-front de-multiplexing transform that includes a second set of wave-front vectors on the N digital data streams in digital domain and outputs concurrently N output data streams such that the N output data streams include M output data streams that correspond respectively to the M input signal streams.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: January 9, 2018
    Assignee: Spatial Digital Systems, Inc.
    Inventors: Donald C.D. Chang, Tzer-Hso Lin, Yuanchang Liu
  • Publication number: 20170373746
    Abstract: A power amplification system comprises a pre-processor including a wavefront multiplexer, a set of power amplifiers, and a post-processor including a wavefront demultiplexer. The wavefront multiplexer receives concurrently N input signals, N being an integer greater than 2, performs a wavefront multiplexing transform on the N input signals by attaching N wavefronts to the N input signals respectively, and generates N first output signals. The N wavefronts are unique and mutually orthogonal. The wavefront multiplexing transform has an inverse. The N power amplifiers amplify the N first output signals and generate N amplified signals. The wavefront demultiplexer performs the inverse of the wavefront multiplexing transform on the N amplified signals and generates N second output signals, the N second output signals corresponding respectively to the N input signals. Each of the N second output signals is an amplified version of a corresponding one of the N input signals.
    Type: Application
    Filed: September 11, 2017
    Publication date: December 28, 2017
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Publication number: 20170366982
    Abstract: A user terminal for transmitting data to a plurality of access points comprises a pre-processor to pre-process at least one source data stream and a multi-beam antenna. The pre-processor comprises a segmenting device to segment the at least one source data stream into a set of N data sub streams, N being an integer greater than 1; a K-muxing unit to perform a N-to-N K-muxing transform on the N data substreams to generate N K-muxed data streams, each of the N K-muxed data streams being a linear combination of the N data substreams; and a bank of modulators to modulate the N K-muxed data streams to generate N K-muxed signal streams. The multi-beam antenna comprises beam forming networks to transform the N K-muxed signal streams into transmit beams, and an array of antenna elements to transmit the transmit beams to the access points.
    Type: Application
    Filed: May 9, 2017
    Publication date: December 21, 2017
    Inventor: Donald C. D. Chang
  • Patent number: 9848094
    Abstract: Presented are cloud storage architectures for private data of scanned documents uploaded from smart phone among terminals with enhanced capability of data privacy and survivability. Pre-processing for storing data in IP cloud comprises: transforming multiple first data sets into multiple second data sets at an uploading site, wherein one of said second data sets comprises a weighted sum of said first data sets; storing said second data sets in an IP cloud via IP connectivity; and storing data in multiple data storages linking to said second data sets at said uploading site. In accordance with an embodiment of present invention post processing may comprise recovering said second data sets at a downloading site via IP network.
    Type: Grant
    Filed: November 6, 2015
    Date of Patent: December 19, 2017
    Assignee: Spatial Digital Systems, Inc.
    Inventors: Donald C. D. Chang, Juo-Yu Lee, Steve K. Chen
  • Publication number: 20170359115
    Abstract: A system for communication comprises an antenna system that includes a reflector having a focus and a feed array positioned at or near the focus and having N feed elements, N being an integer greater than 1. The N feed elements receive N feed signals that result from illumination of the N feed elements by a target signal incident on the reflector from a slow-moving signal source. A first N-to-N Fourier Transform device performs a spatial Fourier Transform on the N feed signals to generate N wavefront signals which are orthogonal to one another. Band-pass filters filter the N wavefront signals and output N filtered wavefront signals. Frequency down-converters down-convert the N filtered wavefront signals to an intermediate frequency or baseband frequency and generate N frequency-down-converted wavefront signals. Analog-to-digital converters digitize the N frequency-down-converted wavefront signals and output N digital wavefront signals.
    Type: Application
    Filed: August 28, 2017
    Publication date: December 14, 2017
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Publication number: 20170346566
    Abstract: A data communication system comprises a central office processor which comprises a first input mapping unit, a first wave-front multiplexer, and a first output mapping unit. The first input mapping unit receives and dynamically maps digital data into a plurality of first electronic signals. The first wave-front multiplexer is coupled to the first input mapping unit to receive the first electronic signals, perform a wave-front multiplexing transformation on the first electronic signals, and output wave-front multiplexed signals, each of the wave-front multiplexed signals being a linear combination of the first electronic signals. The first output mapping unit is coupled to the first wave-front multiplexer to receive and dynamically map the wave-front multiplexed signals into second electronic signals.
    Type: Application
    Filed: July 17, 2017
    Publication date: November 30, 2017
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Patent number: 9829580
    Abstract: A system for reducing undesired interference in a target zone is disclosed. The system comprises a set of M pickup sensors, a beam forming network coupled to the M pickup sensors, and a set of N injectors coupled to the beam forming network. The M pickup sensors pick up undesired signals in real time and generate M pickup signals, M being an integer greater than or equal to 1. The beam forming network comprises a set of M beam forming modules. Each of the M beam forming modules receives a respective one of the M pickup signals and generates N intermediate signals, N being an integer greater than 1. The N intermediate signals generated by each of the M beam forming modules are combined correspondingly with remaining intermediate signals generated by remaining M?1 beam forming modules to generate N interference signals. The N injectors receive and radiate the N interference signals to the target zone.
    Type: Grant
    Filed: November 22, 2016
    Date of Patent: November 28, 2017
    Assignee: Spatial Digital Systems, Inc.
    Inventors: Donald C. D. Chang, Michael T. H. Lin, Steve Chen
  • Publication number: 20170324506
    Abstract: An apparatus comprises a wavefront muxing processor receiving first and second input signals to generate first and second output signals on first and second communication channels, respectively, the first and second output signals being at a common frequency slot and having relative differential amplitude and phase delays; and an amplitude and phase adjustment element located at one of the first and second communication channels to adjust the relative differential amplitude and phase delays using an adjustment amount to reduce interference in the first and second communication channels. The first output signal is a weighted sum of the first input signal and the second input signal that is phase shifted by a second phase shift. The second output signal is a weighted sum of the second input signal and the first input signal that is phase shifted by a first phase shift. The two output signals are transmitted to a transponder.
    Type: Application
    Filed: June 26, 2017
    Publication date: November 9, 2017
    Inventors: Juo-Yu Lee, Donald C.D. Chang, Tzer-Hso Lin
  • Patent number: 9793977
    Abstract: A communications system for providing recovery communication service to users in a coverage area affected by an emergency disruption of normal communication services. The system comprises a ground hub serving as a gateway to terrestrial networks including a dispatch center and configured to communicate with at least three mobile airborne platforms roving over the coverage area via respective feeder-links in a Ku or Ka band. A first mobile airborne platform communicates in a first frequency band with emergency workers that are working in the coverage area and associated with the dispatch center. A second mobile airborne platform communicates, in place of at least one disrupted base station in the coverage area, with user mobile phones in mobile phone frequency bands or user personal devices in WiFi bands located in the coverage area. A third mobile airborne platform generates real-time imaging of surfaces located in the coverage area.
    Type: Grant
    Filed: April 11, 2017
    Date of Patent: October 17, 2017
    Assignee: Spatial Digital Systems, Inc.
    Inventor: Donald C. D. Chang
  • Publication number: 20170286710
    Abstract: One embodiment provides a storage management system. During operation, the system identifies a data file of a user. The system obtains an encrypted client registry from a primary cloud provider in a plurality of cloud providers that provide cloud storage to the user and retrieves a key associated with a device of the user by decrypting the encrypted client registry using a hash of a password associated with the user. The system obtains credentials of the plurality of cloud providers by decrypting a locally stored cloud configuration using the key and generates a plurality of coded fragments from the data file based on a generator matrix of erasure encoding. The number of coded fragments is determined based on a number of the cloud providers associated with the user. The system selects a respective coded fragment for uploading to a corresponding cloud provider in the plurality of cloud providers.
    Type: Application
    Filed: March 23, 2017
    Publication date: October 5, 2017
    Applicant: PhazrIO Inc.
    Inventors: Chi-Kwan J. Cheung, Donald C. D. Chang, Juo-Yu Lee, Steve K. Chen, Tzer-Hso Lin
  • Patent number: 9780859
    Abstract: Aircrafts flying near Earth or naval vessels are used as active scattering platforms in a multipath communications channel in MIMO communications systems. These man-made platforms in a communications channel, with techniques of beam forming and wavefront multiplexing in both transmitters at source and receivers at destinations enhance the ability to coherently combine the power of the communication signals, and improve the signal-to-noise ratio in addition to the MIMO advantage of multiple times of channel capacity over a finite bandwidth via frequency reuse. These platforms may be stationary, mobile ground based, or ocean surface based. They may also be airborne, or space borne. A swarm of 10's micro-UAV based mini-transponders is an example through active scattering of these micro-UAV to generate 10× more available bandwidth between a base station and ground mobile users over same bandwidth.
    Type: Grant
    Filed: February 28, 2014
    Date of Patent: October 3, 2017
    Assignee: Spatial Digital Systems, Inc.
    Inventors: Donald C. D. Chang, Juo-Yu Lee