Patents by Inventor Li Fung Chang

Li Fung 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).

  • Patent number: 7873324
    Abstract: Apparatus and method for processing a received pilot to obtain noise estimation of a pilot channel and processing a received first signal channel, separately from a second signal channel that is orthogonal to the first signal channel, to obtain a signal level of the first signal channel. The noise estimation and the signal level are used to calculate a SNR value. Detection on the first channel is done by checking the SNR and the sign of a soft metric.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: January 18, 2011
    Assignee: Broadcom Corporation
    Inventors: Jun Wu, Hongwei Kong, Li Fung Chang
  • Publication number: 20110002234
    Abstract: Aspects of a method and system for UMTS HSDPA Shared Control Channel processing may include calculating at a receiver, for each one of a plurality of control channels, a quality metric based at least one Viterbi Decoder state metric. A control channel may be selected on the basis of the quality metrics, where the quality metric is selected that provides maximum confidence. The selected control channel may be chosen if its corresponding 3GPP metric is greater than a specified threshold, where the threshold is a design parameter. A validity of a selected control channel may be determined based on consistency and a CRC, where the CRC may be derived from decoding a sub-frame. The calculating and selecting may be done for a first slot of a sub-frame for High-Speed Shared Control Channels.
    Type: Application
    Filed: September 3, 2010
    Publication date: January 6, 2011
    Inventors: LI FUNG CHANG, Hongwei Kong
  • Patent number: 7852239
    Abstract: One or more circuits in a mobile phone may be utilized for up sampling two or more audio signals to a same data sampling rate. Each audio signal, such as digital audio, voice, and polyringer, for example, may be received at one of a plurality of data sampling rates and one or more of the following wireless standards: WCDMA, HSDPA, GSM, GPRS, EDGE, and/or Bluetooth. Audio signals may be equalized and/or compensated with an FIR filter before up sampling or with an IIR filter to reduce overall processing latency. Multiple half-band interpolation operations may perform the up sampling. The first half-band filter may be replaced by an IIR filter to reduce overall processing latency. A gain of the up-sampled data may be adjusted to reduce noise effects. The channels of the up-sampled audio signals may be mixed and later further up sampled for subsequent communication to an output device.
    Type: Grant
    Filed: October 13, 2008
    Date of Patent: December 14, 2010
    Assignee: Broadcom Corporation
    Inventors: Hongwei Kong, Huaiyi (Hanks) Zeng, Nelson Sollenberger, Li Fung Chang, Taiya Cheng, Claude Hayek
  • Patent number: 7826493
    Abstract: Methods and apparatus for acquiring and verifying a code used by a base station. Acquisition time is reduced and circuitry simplified by performing Phase I and Phase II acquisitions in series, but in parallel with Phase III acquisition and verification, which are done in series. Phase III code acquisition is done by despreading the input signal using each of the possible codes in a code group. An estimation of the frequency offset between the base station and the terminal's local reference is used to correct the phase of the despread signals, which are coherently and non-coherently integrated. The largest accumulated value corresponds to the code used by the base station. The code is verified by despreading the received signal, applying a frequency correction, and demodulating. The demodulated output is a series of symbols, and a count of these symbols verifies the acquired code.
    Type: Grant
    Filed: August 26, 2002
    Date of Patent: November 2, 2010
    Inventors: Li Fung Chang, Nelson Sollenberger, Baoguo Yang
  • Patent number: 7814175
    Abstract: A protocol provides generalized client-server computing by providing a server program that can utilize standard and non-standard ports for applications.
    Type: Grant
    Filed: November 16, 2007
    Date of Patent: October 12, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Li Fung Chang, Hui Luo
  • Patent number: 7809092
    Abstract: Aspects of a method and system for UMTS HSDPA Shared Control Channel processing may include calculating at a receiver, for each one of a plurality of control channels, a quality metric derived from at least one Viterbi Decoder state metric. A control channel may be selected on the basis of the quality metrics, where the quality metric is selected that provides maximum confidence. The selected control channel may be chosen if its corresponding 3GPP metric is greater than a specified threshold, where the threshold is a design parameter. A validity of a selected control channel may be determined based on consistency and a CRC, where the CRC may be derived from decoding a sub-frame. The calculating and selecting may be done for a first slot of a sub-frame for High-Speed Shared Control Channels.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: October 5, 2010
    Assignee: Broadcom Corporation
    Inventors: Li Fung Chang, Hongwei Kong
  • Publication number: 20100239050
    Abstract: Aspects of a method and system for signal phase variation detection in communication systems are presented. Aspects of the system may enable detection of phase change between a current received symbol, and one or more previous received symbols. Based on the phase change a channel estimation filter bandwidth may be selected for despreading and/or descrambling one or more subsequent received symbols. In addition, a decision may be made as to whether the subsequent received symbols are to be received based on a closed loop system, or based on an open loop system.
    Type: Application
    Filed: June 1, 2010
    Publication date: September 23, 2010
    Inventors: Li Fung Chang, Hongwei Kong, Nelson Sollenberger
  • Patent number: 7760951
    Abstract: A method and system for pipelined processing in an integrated embedded image and video accelerator is described. Aspects of a system for pipelined processing in an integrated embedded image and video accelerator may include circuitry that enables pipeline processing of video data within a single chip, wherein the pipeline processing may further include decoding of a block of video data while simultaneously inverse transforming a previously decoded block of video data. Aspects of the system may also include circuitry that enables transformation, within the single chip, of a block of said video data while simultaneously encoding, within said single chip, a previously transformed block of video data.
    Type: Grant
    Filed: February 14, 2006
    Date of Patent: July 20, 2010
    Assignee: Broadcom Corporation
    Inventors: Taiyi Cheng, Mark Hahm, Li Fung Chang
  • Publication number: 20100177761
    Abstract: A baseband processing module of a wireless terminal includes a Turbo decoding module. The Turbo decoding module decodes a Turbo code word to produce one or more Media Access Control (MAC) packet(s) carried by the turbo decode word. Each MAC packet includes a MAC packet header and the MAC packet payload, which carries one or more Radio Link Control (RLC) Packet Data Units (PDUs). The Turbo decoding module decodes the MAC packet header to determine boundaries of the PDUs carried in the MAC packet payload. The Turbo decoding module decodes RLC PDU headers and RLC PDU payloads of the RLC PDUs. The Turbo decoding module writes the decoded MAC packet header, the decoded RLC PDU headers, and the decoded RLC PDU payloads to memory in a word-aligned format. The Turbo decoding module may also operate in various other Turbo decoding modes.
    Type: Application
    Filed: July 15, 2009
    Publication date: July 15, 2010
    Applicant: BROADCOM CORPORATION
    Inventors: Xiaoxin Qiu, Li Fung Chang, Hui Luo, Srirang Ashok Lovlekar
  • Patent number: 7756483
    Abstract: RF communications received by a wireless terminal from a servicing base station are used to determine the channel quality such as reported bit error probability (BEP). The RF communications may be in the form of RF bursts that are part of a data frame. An estimated BEP may be determined from the signal to noise ratio (SNR) of the RF bursts and or a sequence of soft decisions extracted from the RF bursts, and their historical performance. The SNR maps to an estimated BEP based upon the modulation format of the RF bursts. The soft decisions decode to produce a data block. When the soft decisions decoded favorably, the re-encoded data block produces a sequence of re-encoded decisions. Comparing the re-encoded decisions to the soft decisions yields a re-encoded bit error (RBER). The reported BEP may be based upon the estimated BEP, RBER, and/or RBER threshold. The RBER threshold may be adaptively incremented or decremented depending upon whether or not the RF communications were properly decoded.
    Type: Grant
    Filed: March 7, 2007
    Date of Patent: July 13, 2010
    Assignee: Broadcom Corporation
    Inventors: Li Fung Chang, Yongqian Wang, Xiaoxin Qiu, Nelson R. Sollenberger
  • Publication number: 20100150165
    Abstract: A method for processing signals in a communication system is disclosed and may include pipelining processing of a received HSDPA bitstream within a single chip. The pipelining may include calculating a memory address for a current portion of a plurality of information bits in the received HSDPA bitstream, while storing on-chip, a portion of the plurality of information bits in the received HSDPA bitstream that is subsequent to the current portion. A portion of the plurality of information bits in the received HSDPA bitstream that is previous to the current portion may be decoded during the calculating and storing. The calculation of the memory address for the current portion of the plurality of information bits may be achieved without the use of a buffer. Processing of the plurality of information bits in the received HSDPA bitstream may be partitioned into a functional data processing path and functional address processing path.
    Type: Application
    Filed: February 22, 2010
    Publication date: June 17, 2010
    Inventors: Li Fung Chang, Mark Hahm, Simon Baker
  • Publication number: 20100146366
    Abstract: A baseband processing module for use within a Radio Frequency (RF) transceiver includes a downlink/uplink interface, TX processing components, a processor, memory, RX processing components, and a turbo decoding module. The RX processing components receive a baseband RX signal from the RF front end, produce a set of IR samples from the baseband RX signal, and transfer the set of IR samples to the memory. The turbo decoding module receives a set of IR samples from the memory, forms a turbo code word from the set of IR samples, turbo decodes the turbo code word to produce inbound data, and outputs the inbound data to the downlink/uplink interface. The turbo decoding module performs metric normalization based upon a chosen metric, performs de-rate matching on the set of IR samples, performs error detection operations, and extracts information from a MAC packet that it produces.
    Type: Application
    Filed: February 2, 2010
    Publication date: June 10, 2010
    Applicant: BROADCOM CORPORATION
    Inventors: Mark David Hahm, Li Fung Chang
  • Publication number: 20100135377
    Abstract: A Radio Frequency (RF) receiver includes a RF front end and a baseband processing module coupled to the RF front end that is operable to receive a time domain signal that includes time domain training symbols and time domain data symbols. The baseband processing module includes a channel estimator operable to process the time domain training symbols to produce a time domain channel estimate, a Fast Fourier Transformer operable to convert the time domain channel estimate to the frequency domain to produce a frequency domain channel estimate, a weight calculator operable to produce frequency domain equalizer coefficients based upon the frequency domain channel estimate, an Inverse Fast Fourier Transformer operable to converting the frequency domain equalizer coefficients to the time domain to produce time domain equalizer coefficients, and an equalizer operable to equalize the time domain data symbols using the time domain equalizer coefficients.
    Type: Application
    Filed: February 10, 2010
    Publication date: June 3, 2010
    Applicant: BROADCOM CORPORATION
    Inventors: Junqiang Li, Mark David Hahm, Nelson R. Sollenberger, Li Fung Chang
  • Patent number: 7729454
    Abstract: Aspects of a method and system for signal phase variation detection in communication systems are presented. Aspects of the system may enable detection of phase change between a current received symbol, and one or more previous received symbols. Based on the phase change a channel estimation filter bandwidth may be selected for despreading and/or descrambling one or more subsequent received symbols. In addition, a decision may be made as to whether the subsequent received symbols are to be received based on a closed loop system, or based on an open loop system.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: June 1, 2010
    Assignee: Broadcom Corporation
    Inventors: Li Fung Chang, Hongwei Kong, Nelson Sollenberger
  • Patent number: 7697596
    Abstract: A system for processing radio frequency (RF) signals includes a searcher and a plurality of Cluster Path Processor (CPPs). The searcher detects a maximum signal energy level and position of at least one of a plurality of individual distinct path signals in a signal cluster of a first information signal, wherein at least a portion of the plurality of individual distinct path signals is received within a duration of a corresponding delay spread. The sampling position is used as a starting sampling location by the plurality of CPPs, including a first information signal CPP and a second information signal CPP. Fine sampling positions of the plurality of CPPs are based upon channel energy estimates for the plurality of individual distinct path signals. CPP outputs are employed to produce channel estimates, which are themselves used in subsequent equalization operations. Sampling positions may change over time in order to satisfy alignment criteria.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: April 13, 2010
    Assignee: Broadcom Corporation
    Inventors: Junqiang Li, Nelson R. Sollenberger, Li Fung Chang, Mark David Hahm, Hongwei Kong
  • Patent number: 7684526
    Abstract: A Radio Frequency (RF) receiver includes a RF front end and a baseband processing module coupled to the RF front end that is operable to receive a time domain signal that includes time domain training symbols and time domain data symbols. The baseband processing module includes a channel estimator operable to process the time domain training symbols to produce a time domain channel estimate, a Fast Fourier Transformer operable to convert the time domain channel estimate to the frequency domain to produce a frequency domain channel estimate, a weight calculator operable to produce frequency domain equalizer coefficients based upon the frequency domain channel estimate, an Inverse Fast Fourier Transformer operable to converting the frequency domain equalizer coefficients to the time domain to produce time domain equalizer coefficients, and an equalizer operable to equalize the time domain data symbols using the time domain equalizer coefficients.
    Type: Grant
    Filed: September 21, 2006
    Date of Patent: March 23, 2010
    Assignee: Broadcom Corporation
    Inventors: Junqiang Li, Mark David Hahm, Nelson R. Sollenberger, Li Fung Chang
  • Patent number: 7684779
    Abstract: A baseband processing module for use within a Radio Frequency (RF) transceiver includes a downlink/uplink interface, TX processing components, a processor, memory, RX processing components, and a turbo decoding module. The RX processing components receive a baseband RX signal from the RF front end, produce a set of IR samples from the baseband RX signal, and transfer the set of IR samples to the memory. The turbo decoding module receives a set of IR samples from the memory, forms a turbo code word from the set of IR samples, turbo decodes the turbo code word to produce inbound data, and outputs the inbound data to the downlink/uplink interface. The turbo decoding module performs metric normalization based upon a chosen metric, performs de-rate matching on the set of IR samples, performs error detection operations, and extracts information from a MAC packet that it produces.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: March 23, 2010
    Assignee: Broadcom Corporation
    Inventors: Mark David Hahm, Li Fung Chang
  • Patent number: 7668188
    Abstract: Methods and systems for processing signals in a communication system are disclosed and may include pipelining processing of a received HSDPA bitstream within a single chip. The pipelining may include calculating a memory address for a current portion of a plurality of information bits in the received HSDPA bitstream, while simultaneously storing on-chip, a portion of the plurality of information bits in the received bitstream that is subsequent to the current portion. A portion of the plurality of information bits in the received HSDPA bitstream that is previous to the current portion may be decoded during the calculating and the storing. The calculation of the memory address for the current portion of the plurality of information bits may be achieved without the use of a buffer. Processing of the plurality of information bits may be partitioned into a functional data processing path and a functional address processing path.
    Type: Grant
    Filed: February 14, 2006
    Date of Patent: February 23, 2010
    Inventors: Li Fung Chang, Mark Hahm, Simon Baker
  • Publication number: 20090287977
    Abstract: A wireless device for implementing Incremental Redundancy (IR) operations includes an IR memory dedicated to storing data related to the IR operations. The IR memory includes a Type I IR memory adapted to store IR status information of a Radio Link Control (RLC) data block and a Type II IR memory adapted to store the RLC data block.
    Type: Application
    Filed: July 23, 2009
    Publication date: November 19, 2009
    Applicant: BROADCOM CORPORATION
    Inventors: Li Fung Chang, Yongqian Wang
  • Patent number: 7603410
    Abstract: A protocol provides generalized client-server computing by providing a server program that can utilize standard and non-standard ports for applications.
    Type: Grant
    Filed: October 13, 2005
    Date of Patent: October 13, 2009
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Li Fung Chang, Hui Luo