Patents Assigned to Atheros Communications
  • Method and system for noise floor calibration and receive signal strength detection
    Patent number: 7643810
    Abstract: A system for detecting the level of the noise floor due to circuit noise as seen at the ADC for a wireless receiver. The system measures power after digitizing and filtering, and subtracts off any variable gain used in the analog front end to determine differentially the size of the signal at the antenna. The system further differentially detects the signal size of any incoming signal at the antenna in a similar fashion, and determines its size relative to the measured noise floor. If the level of the circuit noise of the receiver is known absolutely, the absolute signal size of the incoming signal can likewise be determined with this inventive method and system.
    Type: Grant
    Filed: June 20, 2007
    Date of Patent: January 5, 2010
    Assignee: Atheros Communications, Inc.
    Inventors: Paul J. Husted, William J. McFarland
  • INVOKING DIFFERENT WIRELESS LINK RATE SELECTION OPERATIONS FOR DIFFERENT TRAFFIC CLASSES
    Publication number: 20090323524
    Abstract: Functionality can be implemented within a device or chip to select different sets of wireless link rate determination operations that account for different degrees of presentation time sensitivity that correspond to different classes of traffic. The device or chip can infer or explicitly determine presentation time sensitivity based, at least in part, on traffic class. The selected wireless link rate operations select link rates for the different classes of traffic. A first set of the wireless link rate determination operations can choose a smoother and more stable wireless link rate for the wireless traffic class that conveys presentation time sensitive content. A second of the wireless link rate determination operations can choose a fastest possible wireless link rate, which may be more susceptible to jitter and delay, for a traffic class that is less sensitive.
    Type: Application
    Filed: June 25, 2008
    Publication date: December 31, 2009
    Applicant: Atheros Communications, Inc.
    Inventor: Steven J. Kuhn
  • Data compaction techniques
    Patent number: 7636641
    Abstract: Many areas of technology need highly accurate data compression to provide small, multifunctional devices. In the area of communication governed by the IEEE 802.11 standards, a wireless device could significantly improve its performance by using its calibration data. Moreover, because of the increased mobility of users, a wireless device should be able to operate in different regulatory domains. This flexibility requires access to significant amounts of data regarding such regulatory domains. Advantageously, piecewise linear abstraction and/or mapping can be used to significantly reduce the amount of stored data while ensuring accuracy in reproducing the total data at a later point in time.
    Type: Grant
    Filed: June 5, 2003
    Date of Patent: December 22, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Praveen Dua, David Nakahira, James Hoffman, Fiona Cain
  • Mitigating fractional spurs in fractional-N frequency synthesizer systems
    Patent number: 7636020
    Abstract: One embodiment of the present invention sets forth a technique for mitigating fractional spurs in fractional-n frequency synthesizer circuits. The technique involves advantageously modifying certain least significant bit values in the programming bits of the fractional-n frequency synthesizer circuit to avoid pathological fractional bit patterns. As a result, fractional spurs present in conventional fractional-n frequency synthesizer circuits may be attenuated, thereby improving the overall quality of the resulting out signal.
    Type: Grant
    Filed: May 13, 2008
    Date of Patent: December 22, 2009
    Assignee: Atheros Communications, Inc.
    Inventor: Justin Hwang
  • Decoding system and method for digital communications
    Patent number: 7636400
    Abstract: A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. In another aspect, a system differentiates between data bits based on their estimated reliability, giving more emphasis to decoding reliable bits than unreliable bits using any of a variety of techniques. By differentiating between god and bad bits and de-emphasizing or ignoring unreliable bits, the system can provide a significant reduction in uncorrectable errors and packet loss.
    Type: Grant
    Filed: January 10, 2007
    Date of Patent: December 22, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: John S. Thomson, Paul J. Husted, Ardavan Maleki Tehrani, Jeffrey M. Gilbert, William J. McFarland, Lars E. Thon, Yi-Hsiu Wang
  • SYNTHESIZER AND MODULATOR FOR A WIRELESS TRANSCEIVER
    Publication number: 20090311972
    Abstract: A transceiver including a transmit modulator and a receiver. The modulator may accept a channel selection input, a first modulation input, a second modulation input, and an amplitude input. During transmit time slots, the modulator may generate a modulated output having a carrier frequency selected by the channel selection input. The carrier frequency may be frequency modulated by the first modulation inputs, phase modulated by the second modulation input, and amplitude modulated by the amplitude input. During receive time slots, the modulator may generate a carrier frequency selected by the channel selection input and offset by the first modulation input. The modulator may alternate between providing modulated transmit signals during transmit time slots and providing a local oscillator for the receiver during receive time slots.
    Type: Application
    Filed: July 14, 2008
    Publication date: December 17, 2009
    Applicant: Atheros Communications, Inc.
    Inventors: Paul J. Husted, Soner Ozgur, Xiaoru Zhang
  • POLAR MODULATOR WITH PATH DELAY COMPENSATION
    Publication number: 20090311979
    Abstract: A modulation system comprising a signal processing unit and a modulator. The signal processing unit may generate a low frequency modulator signal, a high frequency modulator signal, and a modulator amplitude control signal. The modulator may generate a modulated signal for transmission via a wireless network based, at least in part, on the low frequency modulator signal, the high frequency modulator signal, and the modulator amplitude control signal. The signal processing unit comprises a delay compensation unit for delaying the generation of the high frequency modulator signal and the modulator amplitude control signal based, at least in part, on signal generation and modulation path delays associated with the low frequency modulator signal to substantially align the modulator signals at the output of the modulation system.
    Type: Application
    Filed: July 14, 2008
    Publication date: December 17, 2009
    Applicant: Atheros Communications, Inc.
    Inventors: Paul J. Husted, William W. Si, David J. Weber, Xiaoru Zhang
  • Wireless channel estimation
    Patent number: 7623467
    Abstract: A system and method are disclosed for wireless channel estimation. Estimating the characteristics of a wireless channel includes receiving a plurality of training symbols sent for the purpose of facilitating channel estimation; calculating a phase difference between at least two of the training symbols; using the calculated phase difference to coherently combine the training symbols to produce a composite training symbol; and using the composite training symbol to estimate the channel.
    Type: Grant
    Filed: September 17, 2003
    Date of Patent: November 24, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Qinfang Sun, Won-Joon Choi, Jeffrey M. Gilbert, Yi-Hsiu Wang
  • PHASE FREQUENCY DETECTOR WITH PULSE WIDTH CONTROL CIRCUITRY
    Publication number: 20090285279
    Abstract: A phase frequency detector comprising a detection circuit and a reset circuit. The phase frequency detector may receive a feedback signal having a predetermined pulse width. The detection circuit may generate a first control signal based on a reference signal, and a second control signal based on the feedback signal. The reset circuit may generate a reset signal used for resetting the detection circuit based on the first control signal, the second control signal, and the feedback signal. The feedback signal may be tied to the generation of the reset signal such that, during a locked state, the pulse width of the second control signal is approximately equal to the pulse width of the feedback signal, which helps reduce the sensitivity of the circuit to nonlinearities.
    Type: Application
    Filed: May 15, 2008
    Publication date: November 19, 2009
    Applicant: Atheros Communications, Inc.
    Inventor: Lalitkumar Nathawad
  • Multi-channel binding in data transmission
    Patent number: 7620028
    Abstract: A system and method are described for binding together a plurality of wireless data communications channels, whereby an aggregate throughput improvement is realized. A master channel amongst the channels to be bound is compatible with existing standards-based wireless data communications equipment. The master channel serves to perform MAC association and flow control. Aggregate throughput is improved by sending and receiving either multiple sets of separately encoded packets, commonly encoded packets or redundantly encoded packets.
    Type: Grant
    Filed: November 6, 2003
    Date of Patent: November 17, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Paul Husted, William John McFarland, Jeffrey M. Gilbert
  • Multiple-input multiple output system and method
    Patent number: 7616698
    Abstract: A multiple-input multiple-output (MIMO) system can transmit on multiple antennas simultaneously and receive on multiple antennas simultaneously. Unfortunately, because a legacy 802.11a/g device is not able to decode multiple data streams, such a legacy device may “stomp” on a MIMO packet by transmitting before the transmission of the MIMO packet is complete. Therefore, MIMO systems and methods are provided herein to allow legacy devices to decode the length of a MIMO packet and to restrain from transmitting during that period. These MIMO systems and methods are optimized for efficient transmission of MIMO packets.
    Type: Grant
    Filed: November 3, 2004
    Date of Patent: November 10, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Qinfang Sun, Won-Joon Choi, Jeffrey M. Gilbert, Ardavan Maleki Tehrani
  • Dual synthesizer RF frequency plan optimized for interference avoidance
    Patent number: 7613430
    Abstract: Using separate synthesizers in a radio frequency (RF) device can facilitate avoiding interference. Specifically, a first synthesizer can be programmed to generate a first output frequency signal having an Frf frequency. A second synthesizer can be programmed to generate a second output frequency signal having an Fif frequency. Notably, a sum of the Frf and Fif frequencies equals an Fchannel frequency of the RF device. Thus, any RF channel can be received (or transmitted) with a plurality of VCO frequencies for each of the two synthesizers. A table of Frf/Fif combinations can be used to determine an Frf/Fif combination that avoids a known interfering source. Alternatively, Frf/Fif combinations can be randomly chosen until an interfering source is avoided.
    Type: Grant
    Filed: December 22, 2005
    Date of Patent: November 3, 2009
    Assignee: Atheros Communications, Inc.
    Inventor: Michael P. Mack
  • Method and apparatus for transmitting and receiving compressed frame of data over a wireless channel
    Patent number: 7609722
    Abstract: A transmitting apparatus and method is described that determines, on a frame-by-frame basis, whether to transmit a compressed frame or a non-compressed frame, depending upon whether the compressed frame or the non-compressed frame will actually be smaller in size. The frame that is smaller is indicated for transmission, with a header of the frame being adapted to include a compression flag indicating whether that frame is the compressed or the non-compressed frame. After wireless transmission and reception, the received frame is, if needed, decompressed if so indicated by the compression flag.
    Type: Grant
    Filed: February 14, 2003
    Date of Patent: October 27, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Jeffrey S. Kuskin, Jeffrey M. Gilbert
  • Apparatus and method for transmission collision avoidance
    Patent number: 7606257
    Abstract: A method of minimizing collisions in a CSMA/CA wireless data communication system using an access point includes sensing the presence of a client desirous of communication with the access point. A start time slot list having at least one unique start time slot during which the client may begin transmitting can be allocated. The start time slot list to the client can be transmitted. A transmission from the client can be received, wherein such transmission begins only during the start time slot(s) indicated by the start time slot list. Notably, the start time slot list can include a high-priority start time slot and a low-priority start time slot substantially equally displaced in time from a center start time slot. A client capable of receiving the start time slot list can select between the high-priority start time slot and the low-priority start time slot based on a randomizing function.
    Type: Grant
    Filed: January 15, 2004
    Date of Patent: October 20, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Craig H. Barratt, William J. McFarland
  • Methods for implementing a dynamic frequency selection (DFS) feature for WLAN devices
    Patent number: 7606193
    Abstract: Various regulatory domains promulgate standards to define how wireless devices should operate in certain frequency bands. The 5 GHz spectrum is of particular importance to certain regulatory domains because of radar systems also operating in this spectrum. To avoid interference with such radar systems, wireless devices operating in this spectrum should be able to detect radar and quickly vacate any channels currently used by the radar systems. Techniques are provided for performing startup scans for radar, identifying backup channels for a possible channel switch, and efficiently changing channels in the event of radar detection in the operating channel. These techniques advantageously meet current regulatory standards governing DFS while minimizing network startup delays and disruption to users during a radar event.
    Type: Grant
    Filed: April 2, 2003
    Date of Patent: October 20, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: William J. McFarland, Michael R. Green
  • Method and apparatus for signal power loss reduction in RF communication systems
    Patent number: 7590390
    Abstract: Multiple power amplifiers in an RF front end are coupled to multiple antennas without diversity switching between the PAs and antennas. Diversity switches direct signals to broadcast by a selected antenna to a PA coupled to the selected antenna. Multiple LNAs are similarly coupled to the diverse antennas. Having one PA and LNA set for each antenna removes the need for diversity switching between the PA/LNAs and each antenna improving signal reception. In one embodiment, a single external PA performs broadcast functions and plural on-chip LNAs are used for reception. In another embodiment, phase shifters are coupled to each PA and LNA, which provide beam forming capability for broadcasts, and in phase signal combinations for received signals.
    Type: Grant
    Filed: January 18, 2007
    Date of Patent: September 15, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: David J. Weber, Manolis Terrovitis, David K. Su
  • HIGH PRECISION POSITIONING SYSTEM
    Publication number: 20090224967
    Abstract: A method for determining a position uses an access point array, a reference station, a location server and a client terminal. The reference station may include a GPS receiver to acquire and track GPS satellites. GPS data may be provided to the location server. The access point array may be configured to minimize interference and may be coupled by a network to the location server. The client terminal may include a GPS receiver. A frequency offset for the client terminal may be determined by examining a frequency offset of the reference station and relative offset frequencies of the access points. This frequency offset may advantageously increase the sensitivity of the client terminal to GPS signals. The client terminal may provide GPS data to the location server, which server may determine the position of the client terminal based on data from the client terminal and the reference station.
    Type: Application
    Filed: March 6, 2008
    Publication date: September 10, 2009
    Applicant: ATHEROS COMMUNICATIONS, INC.
    Inventors: Yi-Hsiu Wang, Qinfang Sun
  • Quasi-balun
    Patent number: 7567142
    Abstract: A quasi-balun circuit for receiving an unbalanced input and providing signals to a balanced-input low noise amplifier (LNA) is provided. Notably, this quasi-balun circuit can provide a phase difference between the positive and the negative terminals of the LNA that is greater than 90 degrees, but less than 180 degrees. In one embodiment, the quasi-balun circuit can provide a phase difference of approximately 135 degrees. To provide this functionality, the quasi-balun circuit includes a passive, reactive network coupled between the unbalanced input and the LNA.
    Type: Grant
    Filed: June 19, 2006
    Date of Patent: July 28, 2009
    Assignee: Atheros Communications, Inc.
    Inventor: Hirad Samavati
  • Method for organizing virtual networks while optimizing security
    Patent number: 7546458
    Abstract: An access point in a wireless communication system can be configured to include multiple virtual LANS (VLANs) based on security levels, thereby allowing secure traffic to be isolated from insecure traffic. Configuring the access point can include assigning a security level to each VLAN and setting a security association for each station associated with the access point. Based on this security association, each station can be assigned to an appropriate VLAN.
    Type: Grant
    Filed: October 18, 2002
    Date of Patent: June 9, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Aman Singla, Andrew M. Davidson, Michael Fine, Kevin Hayes
  • Shield design
    Patent number: D602886
    Type: Grant
    Filed: October 8, 2008
    Date of Patent: October 27, 2009
    Assignee: Atheros Communications, Inc.
    Inventors: Andy Dao, Curtis Lee, Dieter Statezni