Abstract: A method and system for beamforming in a multiple user multiple input multiple output (MIMO) communication system using a codebook may include a processor in a node B that enables generation of an interference cancellation matrix (WR). The interference cancellation matrix, also referred to as a matched filter, may enable a composite signal (Y) to be represented as a plurality of subsidiary signals (yi), each of which is transmitted by the node B for reception at a corresponding ith UE station. Each of the subsidiary signals yi may be generated based on a corresponding one of a plurality of data stream signals (xi). The processor may enable generation of a precoding matrix (WT) based on the interference cancellation matrix. A transmitter within the node B may enable generation of a plurality of signals based on the preceding matrix. The signals may be transmitted via a wireless communication medium.
Abstract: Systems and methods are disclosed for non-preemptive DRAM transactions. More specifically, the present invention relates to improvements in non-preemptive DRAM transactions in real-time unified memory architectures. One embodiment of the present invention relates to a method for determining access to non-preemptive DRAM devices. This method comprises determining real time need for access to the device and prioritizing access using a rate monotonic scheduling.
Abstract: A system and method for pre-detection in a power over Ethernet (PoE) system. A power sourcing equipment (PSE) is designed to measure a port voltage upon application of a small current source. A microcontroller controls the current source based on a comparison of the measured port voltage to a threshold voltage.
Abstract: Certain aspects of a digital baseband transmitter with digital RF/IF support in GSM/GPRS/EDGE compliant devices may comprise receiving digitized data within a chip. A control signal may be generated within the chip indicating whether the received digitized data is to be processed by an IF processing interface or a digital RF processing interface. The baseband processor has the capability to work together with different kinds of RF chips on the market and since this design is implemented on a single module, most of the circuits are shared which reduces the die size significantly. This design also provides a customer more flexibility to choose among different RF vendors.
Abstract: Improved decision feedback equalizer and decision directed timing recovery systems and methods suitable for use in connection with a dual mode QAM/VSB receiver system are disclosed. A trellis decoder operates in conjunction with a decision feedback equalizer circuit on trellis coded 8-VSB modulated signals. The trellis decoder includes a 4-state traceback memory circuit outputting a maximum likelihood decision as well as a number of intermediate decisions based upon the maximum likelihood sequence path. Any number of decisions, along the sequence, may be provided as an input signal to timing recovery system loops, with the particular decision along the sequence chosen on the basis of its delay through the trellis decoder. Variable delay circuitry is coupled to the other input of the timing recovery system loops in order to ensure that both input signals bear the same timestamp.
Type:
Grant
Filed:
December 8, 2008
Date of Patent:
January 17, 2012
Assignee:
Broadcom Corporation
Inventors:
Tian-Min Liu, Loke Kun Tan, Steven T. Jaffe
Abstract: Certain aspects of a method and system for an antenna architecture for multi-antenna orthogonal frequency division (OFD) based systems are disclosed. Aspects of one method may include communicating data in a radio frequency (RF) system comprising a plurality of antennas, via at least one polarized antenna that is orthogonally polarized with respect to adjacent polarized antennas. The plurality of coherently polarized antennas may be placed at a particular distance from each other.
Abstract: Certain aspects of the method may comprise receiving a plurality of spatially multiplexed communication signals from a plurality of transmit antennas at a base station. A plurality of vectors of baseband combined channel estimates may be generated based on phase rotation of the received plurality of spatially multiplexed communication signals. A plurality of pre-equalization weights may be generated based on the generated plurality of vectors of baseband combined channel estimates. The received plurality of spatially multiplexed communication signals may be modified based on the generated plurality of pre-equalization weights. At least a portion of the generated plurality of pre-equalization weights may be fed back to the base station for modifying subsequently transmitted spatially multiplexed communication signals which are transmitted from at least a portion of the plurality of transmit antennas at the base station.
Type:
Grant
Filed:
June 30, 2005
Date of Patent:
January 17, 2012
Assignee:
Broadcom Corporation
Inventors:
Mark Kent, Vinko Erceg, Uri M. Landau, Pieter Van Rooyen, Pieter Roux
Abstract: A method and apparatus for tracking a signal comprises correlating a digital signal with a code using a hypothesis at a plurality of frequencies and at least one delay to produce correlation results, measuring an energy value of the correlation results, adjusting at least one of the frequency or delay in response to the measured energy value to form the hypothesis.
Abstract: A method for point-to-point ethernet communication over point-to-multipoint shared single conductor channel topology comprises transmitting an ethernet signal upstream over the point-to-multipoint topology from one end point of the topology to the root of the topology, transmitting the ethernet signal downstream over the point-to-multipoint topology from the root of the topology to all end points of the topology, and selectively processing only at a designated end point the ethernet signal received at all end points. An ethernet system may comprise single conductor channel cabling (e.g., coaxial cabling) including a trunk line and a plurality of branch lines connecting to the trunk line at a plurality of points along the trunk line, a single root transceiver (root-PHY) connected at an end of the trunk line, and a plurality of end point transceivers (EP-PHYs), each connected to a respective one of the plurality of branch lines.
Abstract: Apparatus and methods for estimating transmission noise in a programming information signal. Channel noise power in binary phase shift keying (“BPSK”) modulated telecommunication may be estimated. Such a method may include receiving over the channel a reference signal and a data BPSK signal. The data BPSK signal may include the programming information. The method may include formulating a channel transfer function estimate for the channel based on the reference signal. The estimate may include a channel estimation error. The data BPSK signal may be equalized using the transfer function estimate. The data BPSK signal may include noise, which may be quantified in terms of power. The data BPSK signal noise power may be estimated in such a manner that is independent of the channel estimation error.
Abstract: A preamble of a frame for a multiple input multiple output (MIMO) wireless communication for a first transmit antenna of the MIMO communication includes a legacy preamble portion in accordance with a legacy wireless communication protocol. The preamble of the frame for the MIMO wireless communication for the first transmit antenna also includes a current protocol preamble portion in accordance with a protocol of the MIMO wireless communication. The preamble of a frame for at least a second antenna of the MIMO communication includes a cyclically shifted legacy preamble portion for the frame. The preamble of the frame for the MIMO wireless communication for the second transmit antenna also includes a second current protocol preamble portion in accordance with a protocol of the MIMO wireless communication.
Type:
Application
Filed:
September 21, 2011
Publication date:
January 12, 2012
Applicant:
BROADCOM CORPORATION
Inventors:
Christopher J. Hansen, Jason A. Trachewsky, R. Tushar Moorti, Christopher Young
Abstract: A system, method and computer program product that facilitates communication between devices that implement at least one proprietary feature in a DOCSIS-compliant broadband communication system. A logical channel is established for communication between a first device, such as a cable modem termination system (CMTS), that implements at least one proprietary feature, and other devices that also implement the at least one proprietary feature. Registration information is then received from a second device, such as a cable modem, wherein the registration information indicates that the second device also implements the at least one proprietary feature. In response to receiving the registration information, the second device is assigned to the logical channel.
Abstract: A technique is described herein for reducing audible artifacts in an audio output signal generated by decoding a received frame in a series of frames representing an encoded audio signal in a predictive coding system. In accordance with the technique, it is determined if the received frame is one of a predefined number of received frames that follow a lost frame in the series of the frames. Responsive to determining that the received frame is one of the predefined number of received frames, at least one parameter or signal associated with the decoding of the received frame is altered from a state associated with normal decoding. The received frame is then decoded in accordance with the at least one parameter or signal to generate a decoded audio signal. The audio output signal is then generated based on the decoded audio signal.
Type:
Application
Filed:
September 22, 2011
Publication date:
January 12, 2012
Applicant:
BROADCOM CORPORATION
Inventors:
Jes Thyssen, Juin-Hwey Chen, Robert W. Zopf
Abstract: Disclosed is a high efficiency amplifier operable to substantially reduce electromagnetic interference (EMI). The high efficiency amplifier comprises an output stage to provide a high powered signal to a load. The high efficiency amplifier further comprises an overlap protection circuit to produce a timing non-overlap in a control signal for the output stage, and an edge control circuit to reduce a transient portion of the high powered signal to substantially reduce the EMI. The overlap protection circuit and the edge control circuit may be implemented with resistive source degeneration. Also disclosed is a related method. In one embodiment, the high efficiency amplifier and the related method may be incorporated into a cellular telephone or a mobile audio device.
Abstract: A system and method is provided for phase interpolator based transmission clock control. The system includes a transmitter having a phase interpolator coupled to a master timing generator and a transmission module. The phase interpolator is also coupled to a receiver interpolator control module and/or an external interpolator control module. When the system is operating in repeat mode, the transmitter phase interpolator receives a control signal from a receiver interpolator control module. The transmitter phase interpolator uses the signal to synchronize the transmission clock to the sampling clock. When the system is operating in test mode, a user defines a transmission data profile in an external interpolator control module. The external interpolator control module generates a control signal based on the profile. The transmitter phase interpolator uses the signal to generate a transmission clock that is used by the transmission module to generate a data stream having the desired profile.
Type:
Application
Filed:
September 21, 2011
Publication date:
January 12, 2012
Applicant:
Broadcom Corporation
Inventors:
Aaron W. Buchwald, Michael Le, Hui Wang, Howard A. Baumer, Pieter Vorenkamp
Abstract: A circuit for producing one of a plurality of output clock frequencies from a single, constant input reference clock frequency. The circuit comprises a reference clock system and a phase lock loop. The reference clock system includes a bypass path, a divider path including a first integer divider, and a multiplexer. A divisor of the first integer divider is based on a selected communications protocol of a group of possible communications protocols. The multiplexer is configured to route the bypass path or the divider path based on the selected communications protocol. The phase lock loop includes a voltage controlled oscillator and a feedback path. The feedback path includes a second integer divider. A divisor of the second integer divider is based on the selected communications protocol. The reference clock system is configured to receive a constant reference clock frequency.
Type:
Application
Filed:
August 20, 2010
Publication date:
January 12, 2012
Applicant:
Broadcom Corporation
Inventors:
Jun CAO, Afshin MOMTAZ, Chung-Jue CHEN, Kang XIAO, Vivek TELANG, Ali GHIASI
Abstract: A multi-mode RFID tag includes a power generating and signal detection module, a baseband processing module, a transmit section, a configurable coupling circuit, and an antenna section. In near field mode, the configurable coupling circuit is operable to couple the transmit section to a coil or inductor in the configurable coupling circuit to transmit an outbound transmit signal using electromagnetic or inductive coupling to an RFID reader. In far field mode, the configurable coupling circuit is operable to couple the transmit section to the antenna section, and the multi-mode RFID tag then utilizes a back-scattering RF technology to transmit the outbound transmit signal to RFID readers.
Abstract: A device for handing off a wireless connection can include a receiver configured to receive a communication signal from a wireless device within a first wireless cell, a first processor configured to determine communication information regarding the first wireless cell, and a storage unit configured to store directional information regarding the first wireless cell. In addition, the device can have a transmitter configured to transmit the directional information to a wireless device located within the first wireless cell, and a second processor configured to provide wireless connection to the wireless device through the receiver and the transmitter. The second processor can Handoff the wireless connection to a second wireless cell.
Abstract: At least a first capacitor is formed on a substrate and connected to a first differential node of a differential circuit, and the first capacitor may be variable in capacitance. A second capacitor is formed on the substrate and connected to a second differential node of the differential circuit, and the second capacitor also may be variable. A third capacitor is connected between the first differential node and the second differential node, and is formed at least partially above the first capacitor. In this way, a size of the first capacitor and/or the second capacitor may be reduced on the substrate, and capacitances of the first and/or second capacitor(s) may be adjusted in response to a variable characteristic of one or more circuit components of the differential circuit.
Abstract: A radio transceiver device includes circuitry for radiating electromagnetic signals at a very high radio frequency both through space, as well as through wave guides that are formed within a substrate material. In one embodiment, the substrate comprises a dielectric substrate formed within a board, for example, a printed circuit board. In another embodiment of the invention, the wave guide is formed within a die of an integrated circuit radio transceiver. A plurality of transceivers with different functionality is defined. Substrate transceivers are operable to transmit through the wave guides, while local transceivers are operable to produce very short range wireless transmissions through space. A third and final transceiver is a typical wireless transceiver for communication with remote (non-local to the device) transceivers.