Patents by Inventor C.D. Chang

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: 20230229613
    Abstract: An input switching circuit dynamically connects, based on an input mapping table, input streams to inputs of a wavefront pre-transform circuit. An output switching circuit dynamically connects, based on an output mapping table, output data at outputs of the wavefront pre-transform circuit to transport streams. A controller controls, based on a wiping command, at least one of the input and output switching circuits to alter at least one of the input and output mapping tables such that the at least one of the input and output switching circuits is disabled for connection. A first subset of the transport streams operates in a foreground mode available to a user and is transported for storage in remote storage sites at a network and a second subset of the transport streams operates in a background mode available to an administrator and is not transported for storage in the remote storage sites.
    Type: Application
    Filed: March 6, 2023
    Publication date: July 20, 2023
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Juo-Yu Lee, Donald C.D. Chang, Steve K. Chen
  • Publication number: 20230145659
    Abstract: A communication system comprises a remote digital beam-forming network configured to receive a set of input signals destined for a set of user devices and generate element signals to be radiated by a set of remote antenna array elements; a pre-processor coupled to the remote digital beam-forming network, configured to perform a wavefront multiplexing transform on signal waveforms including the element signals and generate wavefront multiplexed signals; an optical line terminal coupled to the pre-processor, configured to process the wavefront multiplexed signal streams to generate optical waveform streams; and optical fibers coupling the optical line terminal to a set of optical network units.
    Type: Application
    Filed: January 9, 2023
    Publication date: May 11, 2023
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Steve K. Chen
  • Patent number: 11552699
    Abstract: A MIMO basestation for a cellular communications system comprises a remote indoor processing facility coupled to an outdoor RF tower via optical fibers. The remote indoor processing facility includes a bank of RF modulators to modulate signal streams; a remote MIMO transmitting processor that includes a remote digital beam-forming network to transform the modulated signal streams into transmit beam signals; a pre-processor to perform a wavefront multiplexing transform on the transmit beam signals to generate wavefront multiplexed beam signals, each of the wavefront multiplexed beam signals being a linear combination of the transmit beam signals; and RF-to-optical drivers to perform optical modulating functions on the wavefront multiplexed beam signals to generate optical waveform streams.
    Type: Grant
    Filed: November 18, 2019
    Date of Patent: January 10, 2023
    Assignee: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Steve K. Chen
  • Publication number: 20220329294
    Abstract: An active scattering device comprises a set of N identical single chain RF devices functioning as repeaters or transponders, which are placed adjacent to each other and in parallel over an area of active scattering, where N is an integer ?2. Each of the N identical RF devices includes a receiving aperture, having a first coverage, for receiving a first signal within the first coverage; and a transmitting aperture, having a second coverage, for re-radiating a second signal within the second coverage, the second signal being received by one of the respective receiving apertures of the N identical RF devices. In various embodiments, the active scattering device is configured to function as a reflective directional repeater/transponder, or a retro-directive repeater/transponder, or a 2-D directional repeater/transponder that is retro-directive in a first dimension and reflective in a second dimension perpendicular to the first dimension.
    Type: Application
    Filed: June 20, 2022
    Publication date: October 13, 2022
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee
  • Publication number: 20200099464
    Abstract: An apparatus comprises an antenna array having N elements to receive N input streams from a plurality of transmitters and a post-processing device to perform a wavefront de-multiplexing transform on the N input streams corresponding to M orthogonal beams to generate M output streams using a weight matrix having M beam weight vectors (BWVs) associated with the M orthogonal beams, where M and N are positive integers and 1<M?N. The M BWVs are calculated using an optimization procedure based on performance constraints. The performance constraints for one of the M orthogonal beams with an orthogonal beam radiation pattern include designated peak and null positions.
    Type: Application
    Filed: November 25, 2019
    Publication date: March 26, 2020
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Tzer-Hso Lin
  • Publication number: 20200091997
    Abstract: A MIMO basestation for a cellular communications system comprises a remote indoor processing facility coupled to an outdoor RF tower via optical fibers. The remote indoor processing facility includes a bank of RF modulators to modulate signal streams; a remote MIMO transmitting processor that includes a remote digital beam-forming network to transform the modulated signal streams into transmit beam signals; a pre-processor to perform a wavefront multiplexing transform on the transmit beam signals to generate wavefront multiplexed beam signals, each of the wavefront multiplexed beam signals being a linear combination of the transmit beam signals; and RF-to-optical drivers to perform optical modulating functions on the wavefront multiplexed beam signals to generate optical waveform streams.
    Type: Application
    Filed: November 18, 2019
    Publication date: March 19, 2020
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Steve K. Chen
  • Publication number: 20190363784
    Abstract: A communications system includes a ground hub, mobile airborne platforms, and a user terminal. The ground hub includes an antenna system, a beam-forming system and a baseband processor. The antenna system receives return-link signals radiated respectively by the mobile airborne platforms. The return-link signals correspond to signal streams transmitted by the user terminal and received by the mobile airborne platforms. The signal streams correspond to data streams including a known pilot code stream. The beam-forming system forms beams to receive the return-link signals and transforms the received return-link signals into baseband signals. The baseband processor includes adaptive equalizers to equalize the baseband signals and a wavefront demultiplexing processor to perform a wavefront demultiplexing transform on the equalized baseband signals to produce recovered versions of the data streams.
    Type: Application
    Filed: July 22, 2019
    Publication date: November 28, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Publication number: 20190356048
    Abstract: An antenna system includes N movable antenna elements configured to generate concurrently M receiving beams pointing respectively at M satellites radiating in a common frequency band, N and M being integers and N?M?2. A beam forming system is coupled to the N movable antenna elements and configured to shape the M receiving beams using weights inputted from a beam controller. The beam controller optimizes the M receiving beams by computing spatial displacements to spatially reposition the N movable antenna elements relative to each other, using an iterative optimization processing to satisfy a plurality of constraints concurrently. A position driver system spatially re-positions the N movable antenna elements in accordance to the spatial displacements inputted from the beam controller.
    Type: Application
    Filed: July 29, 2019
    Publication date: November 21, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Tzer-Hso Lin, Eric Hu
  • Publication number: 20190312847
    Abstract: A communications system between a source and a destination includes a transmitter at the source and a communication connectivity. The transmitter comprises a preprocessor and a candidate envelope folder to provide M known a priori digital envelopes, M?1. The preprocessor has N input ports and N output ports, N>M, performs at least one wavefront multiplexing (WFM) transform on N inputs received at the N input ports to generate N outputs at the N output ports. The preprocessor performs the at least one WFM transform by calculating, for each of the N outputs, a linear combination of the N inputs using one of the M digital envelopes such that a digital format of one of the N outputs appears to human sensors as having features substantially identical to a digital format of the one of the M digital envelopes.
    Type: Application
    Filed: June 24, 2019
    Publication date: October 10, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Steve K. Chen
  • Publication number: 20190266340
    Abstract: An apparatus includes a memory storing a digital envelope and a wavefront demultiplexing (WFD) device which receives M input streams concurrently, M being an integer greater than 1, performs a WFD transformation on the M input streams, and generates M output streams concurrently. A first input stream includes wavefront multiplexed digital identifiers for digital right management. A second input stream is the digital envelope. The first input stream presented in a digital format appears to human perception as having identical features to the digital envelope presented in the digital format. Each output stream is a linear combination of the M input streams such that the digital identifiers are recovered from at least one of the M output streams. The digital envelope is a data file used by a sender to send the M input streams and is scaled with a magnification factor greater than 1 in the WFD transformation.
    Type: Application
    Filed: May 13, 2019
    Publication date: August 29, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Jeffrey C. Chang, Steve K. Chen
  • Publication number: 20190108178
    Abstract: An apparatus includes N audio receivers positioned in a pre-defined geometry with respect to P audio sources to receive P audio signals from the P audio sources; N data sets coupled to the N audio receivers to sample the received P audio signals into N data streams; a plurality of storage devices coupled to the N data sets to store the N data streams; and a post processor coupled to the plurality of storage devices to generate output signals corresponding to reconstituted P audio signals using a wavefront demultiplexing transformation, wherein N and P are positive integers and N?P. The post processor has inputs receiving data retrieved from the plurality of storage devices and outputs providing the output signals.
    Type: Application
    Filed: December 11, 2018
    Publication date: April 11, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Steve K Chen
  • Publication number: 20190044582
    Abstract: A communications system includes at least one receiver having receiving elements and a transmitter having transmitting elements to transmit signals to the receiving elements via wireless propagation channels. The transmitter includes a beam-forming network and a channel measurement unit. The beam-forming network receives input signal streams at its input ports and outputs one or more signals as shaped beams based on a set of composited transfer functions. The channel measurement unit performs measurements of components of channel status information to generate a set of point-to-point transfer functions and generates the composited transfer functions by computing linear combinations of the point-to-point transfer functions. Each of the point-to-point transfer functions characterizes propagation paths from one of the transmitting elements to one of the receiving elements.
    Type: Application
    Filed: October 2, 2018
    Publication date: February 7, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee
  • Publication number: 20190034108
    Abstract: A pre-processing apparatus includes a segmenter, a wavefront multiplexing (WFM) processor, and a network interface. The segmenter segments a media file or a plurality of media files into N media components using a data formatting scheme. The WFM processor transforms the N media components to N transformed components on a sample basis or a block basis according to the data formatting scheme. Each of the N transformed components is a linear combination of the N media components. The network interface transmits the N transformed components to a server for storage as a document file on a remote storage via a network connectivity.
    Type: Application
    Filed: September 18, 2018
    Publication date: January 31, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee, Steve K. Chen
  • Publication number: 20190020403
    Abstract: A communication system includes (1) a first airborne linear array configured to project a first fan beam over a first ground coverage elongated in a first direction, the first fan beam delivering a first information data associated with a first data stream; and (2) a second airborne linear array configured to project a second fan beam over a second ground coverage elongated in a second direction, the second fan beam delivering a second information data associated with a second data stream. The first and second ground coverages are overlapped to form a common coverage area. The first and second data streams are complementary to each other and are linear combinations of a plurality of segmented substreams. The plurality of segmented substreams is formed from an information data stream. The first and second data streams are generated from a ground control facility.
    Type: Application
    Filed: June 26, 2018
    Publication date: January 17, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee
  • Publication number: 20190020397
    Abstract: A communication system includes a transmitter and remote receivers having each a set of receive elements. The transmitter includes a preprocessor and a set of transmit elements which radiate shaped beams including probing signals through a multipath communication channel. The preprocessor computes channel state information based on received responses to the probing signals, generate composited transfer functions based on the channel state information, generate the shaped beams based on the composited transfer functions, and process a plurality of input signals to be transmitted via the shaped beams to the remote receivers. The channel state information includes transfer functions, each characterizing at least one propagation path from one transmit element to one receive element. Each composited transfer function is a linear combination of the transfer functions. Each receive element is identified by a user element identification index in the transfer functions.
    Type: Application
    Filed: September 4, 2018
    Publication date: January 17, 2019
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Donald C.D. Chang, Juo-Yu Lee
  • Patent number: 10120873
    Abstract: Presented is a multi-channel data process to utilize wavefront multiplexing for data storage and data stream transport with redundancy on cloud or in a distribution network. This processing features additional applications for multi-media recording and data communications via transponding platforms including satellites, unmanned air vehicles (UAVs), or others for better survivability and faster accessing. Multiple concurrent data streams are pre-processed by a wavefront multiplexer into multiple sub-channels or wavefront components, where signals from respective data streams are replicated into sub-channels. These replicated data streams are linked via a unique complex weighting vector (amplitude and phase or their equivalents), or “wave-front”, which are also linked by various spatially independent wavefronts. Additionally, probing data streams are embedded and linked via some of the independent wavefronts. Aggregated data streams in sub-channels are unique linear combinations of all input data streams.
    Type: Grant
    Filed: May 14, 2015
    Date of Patent: November 6, 2018
    Assignee: SPATIAL DIGITAL SYSTEMS, INC.
    Inventors: Juo-Yu Lee, Donald C.D. Chang, Steve K. Chen
  • Publication number: 20180302150
    Abstract: An apparatus includes a demultiplexing device, a bank of filters, a wavefront processor, and an optimizer. The demultiplexing device demultiplexes M data streams into N wavefront signals which include P pilot signals, N, M, and P being positive integers and N>M. The bank of filters filters the N wavefront signals using filter weights. The wavefront processor, having N input ports and N output ports, performs an N-to-N wavefront demultiplexing transform on the N wavefront signals at the N input ports and outputs N wavefront demultiplexed signals at the N output ports such that each of the N wavefront demultiplexed signals is a linear combination of the N wavefront signals. The N wavefront demultiplexed signals include P recovered pilot signals. The optimizer updates the filter weights using performance indices based on the P recovered pilot signals and known pilot signals corresponding to the P pilot signals.
    Type: Application
    Filed: June 19, 2018
    Publication date: October 18, 2018
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Publication number: 20180226982
    Abstract: A broadband linear processing system includes a pre-processing module and a set of M linear processors coupled to the pre-processing module, M being an integer greater than 1. The pre-processing module includes a wavefront multiplexer having M input ports and M output ports. The wavefront multiplexer receives M input signals at the M input ports, performs a wavefront multiplexing transform on the M input signals and outputs M narrowband signal streams at the M output ports. The wavefront multiplexing transform has an inverse. Each of the M linear processors receives and processes a corresponding one of the M narrowband signal streams, and outputs a corresponding one of M processed narrowband signal streams.
    Type: Application
    Filed: April 2, 2018
    Publication date: August 9, 2018
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Publication number: 20180205583
    Abstract: A system for remotely generating beams to be concurrently radiated by a downlink broadcast antenna array having N array elements onboard a satellite, N being an integer>1, includes a ground station comprising a digital beam forming (DBF) processor, a wavefront multiplexer, and D/A converters. The DBF processor applies beam weight vectors which include information on a footprint and a pointing direction of a beam to a content data stream and generates N data streams. The wavefront multiplexer having M input ports and M output ports, M being an integer?N, receives the N data streams and M?N diagnostic streams at the M input ports, performs a spatial transform on the M input streams to generate M output streams. The D/A converters convert respectively the M output streams to M baseband signals which are then transformed into an uplink signal to be transmitted to the satellite.
    Type: Application
    Filed: March 12, 2018
    Publication date: July 19, 2018
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang
  • Publication number: 20180205448
    Abstract: A system for communications via first and second transponders includes a transmitter in a ground hub and a VSAT on a moving platform. The transmitter includes a beam shaping processor for forming concurrently first and second beams to transmit first and second streams of data to the VSAT via the first and second transponders, respectively. The VSAT comprises an array antenna, a beam forming network, Rx/Tx processors, and a mini-hub. The array antenna includes N discrete elements arranged as a distributed array and mounted on a fixed structure, N>1. The beam forming network, remotely located from the array antenna and coupled to the array antenna wirelessly or via a fiber, forms concurrent tracking beams for the array antenna to track the transponders. The Rx/Tx processors perform communications functions including modulation, demodulation, channelization, frequency tracking, and timing synchronization. The mini-hub communicates wirelessly with user devices onboard the moving platform.
    Type: Application
    Filed: March 13, 2018
    Publication date: July 19, 2018
    Applicant: SPATIAL DIGITAL SYSTEMS, INC.
    Inventor: Donald C.D. Chang