Advanced Micro Devices Corporation

Globalfoundries Inc.

Globalfoundries U.S. Inc.

Uwe Eckhardt

Eric Sachse

Michael Schmidt

Menno Mennenga

Jörg Borowski

Matthias Baer

Ralf Flemming

Ingo Kühn

Tilo Ferchland

Thomas Hanusch

Frank Poegel

Michael Grell

Dirk Fimmel

Axel Wachtler

Juergen Boldt

Karl-Heinz Sandig

Joerg Borowski

Matthias Lenk

Attila Roemer

Ingo Kuehn

Falk Tischer

Steffen Hofmann

The present disclosure relates to a structure including a first curvature compensation circuit which includes a first set of transistors, and a second curvature compensation circuit which includes a second set of transistors. A voltage reference (VREF) signal output from a bandgap voltage reference core with the second curvature compensation circuit is received as an input to the first curvature compensation circuit.

Curvature compensation circuits for bandgap voltage reference circuits

The present disclosure relates to circuit structures and, more particularly, to circuit structures which detect high speed and high precision characterization of VTsat and VTlin of FET arrays and methods of manufacture and use. The circuit includes a control loop comprised of a differential amplifier, a plurality of FET arrays, and at least one analog switch enabling selection between a calibration mode and an operation mode.

High speed and high precision characterization of VTsat and VTlin of FET arrays

A ciphering key management technique for use in a WLAN receiver is provided where a hash table is stored that has a first and a second table portion. The first table portion stores transmitter address data and the second table portion stores at least one cipher key. It is determined whether a transmitter address matches transmitter address data in the first table portion, and if so, a corresponding cipher key stored in the second table portion is determined for use in decrypting the received data. The hash table technique allows for a fast search for the correct cipher key. Embodiments are described that allow for dynamically adding and removing keys without blocking the search.

Fast ciphering key search for WLAN receivers

A method of performing encrypted WLAN communication is provided that comprises the steps of performing a connection set-up for the encrypted WLAN communication and performing data frame encapsulation and/or decapsulation during the encrypted WLAN communication. The connection set-up is performed by executing software-implemented instructions, and the data frame encapsulation and/or decapsulation is performed by operating single-purpose hardware. In embodiments, corresponding single-purpose hardware devices, integrated circuit chips, computer program products and computer systems are provided. The embodiments may provide an improved hardware/software architecture for 802.11i security enhancement.

Hardware/software partitioning for encrypted WLAN communications

A communication device for performing cryptographically secured communication in a WLAN (Wireless Local Area Network) network is provided that comprises a security enhancement unit and a MAC (Medium Access Control) unit. The security enhancement unit is for encrypting plaintext data frames into encrypted data frames and/or decrypting encrypted data frames into plaintext data frames. The MAC unit is for managing communication between communication devices within the WLAN network by coordinating access to a shared wireless communication medium through which communication signals are transmitted. The security enhancement unit and the MAC unit are adapted to perform an on-the-fly encryption process and/or on-the-fly decryption process thereby exchanging the encrypted data frames without buffering the encrypted data frames after encryption or prior to decryption, respectively. The embodiments may provide an improved encryption/decryption architecture including an on-chip memory for performing on-the-fly encryption and/or on-the-fly decryption in the framework of 802.11i security enhancement.

On-the-fly encryption/decryption for WLAN communications

A WLAN (Wireless Local Area Network) transmitter or another data communications apparatus is provided that includes a transmission section that is configured to generate signals to be transmitted, and a control section that is connected to the transmission section to control the transmission section dependent on at least two transmission parameters. The control section comprises a state transition controller that is configured to step through a plurality of predefined control states. The control section is configured to apply different transmission parameter modification mechanisms in different control states. The state transition controller is configured to determine the respective next control states based on transmission success and failure statistics.

Transmitter adjustment based on transmission statistics

A WLAN (Wireless Local Area Network) receiver is provided that provides at least two acquisition units and at least two tracking units. The acquisition units perform a synchronization acquisition process, and the tracking units perform a synchronization tracking process. The acquisition units are arranged for being operated sequentially while the tracking units are arranged for being operated simultaneously. In an embodiment, frequency and phase error correction may be performed separately, and those units that operate at higher sampling rates may be located before lower-rate units. The synchronization process may include data-aided as well as non data-aided algorithms.

Wireless LAN receiver synchronization

An improved decision feedback equalization technique is provided that may be used in data communications receivers such as those in WLAN (Wireless Local Area Network) systems. The decision feedback equalizer comprises a feedforward filter that is connected to receive an input data signal and output a filter representation thereof. The feedforward filter has a filter characteristic that depends on filter coefficient data. The decision feedback equalizer further comprises a filter coefficient computation unit for generating the filter coefficient data and outputting the generated data to the feedforward filter. At least one data processing circuit is provided that receives a mode switch signal for switching its operational mode. The data processing circuit is arranged for performing a feedforward filter function in one operational mode and a filter coefficient computation function in another operational mode.

Decision feedback equalizer having reduced gate count

A receiving unit in a communication system for receiving a communication signal. The receiving unit is preferably a wireless local area network (WLAN) receiver. The receiving unit comprises a synchronization data detection section and a frequency error correction section. The synchronization data detection section detects predefined synchronization data included in the received communication signal and computes an initial estimate of a frequency error of the received communication signal. The frequency error correction section corrects the frequency of the received communication signal based on frequency error estimates. An initial frequency error estimate used for a first frequency error correction is received from said synchronization data detection.

Frequency error correction unit and method in a wireless LAN system

A timing error correction technique for use in data communications receivers such as WLAN (Wireless Local Area Network) receivers is provided where an input signal is received that has a timing error, the timing error is corrected, and a signal having a corrected timing error is output. The timing error correction comprises performing an early-late correlation on the signal that has the corrected timing error. The early-late correlation comprises the generation of at least one early and late sample pair, the generation of an error signal that is indicative of the difference between the early and late samples, and the generation of at least one control signal based on the error signal. A time offset correction algorithm is performed dependent on the control signal.

Early-late correlation for timing error correction in data communication receivers

An average tracking mechanism for a data communication receiver is provided. The average tracking mechanism of the receiver is connected to receive an input stream of data samples and is adapted to keep track of an average over a predefined number of most recently received data samples. The average tracking mechanism comprises a calculation unit that is adapted to calculate an approximate value of the average and a storage unit for storing calculated approximate values. The calculation unit is adapted to calculate the approximate value by retrieving a previously calculated approximate value from the storage unit and calculating a weighted sum of the retrieved approximate value and a current data sample. The average approximation technique may be used in a comb filter of a preamble detector in a WLAN receiver.

Average tracking mechanism in data communications receivers

A complementary code decoder technique is provided where the encoded input data is first parallelized. From the parallelized data, correlation values are generated by a correlator circuit that is capable of changing its correlation characteristics depending on at least one control signal. Different control signals are sequentially provided to the correlator circuit thereby driving the correlator circuit to sequentially generate multiple correlation values from the parallelized data, based on different correlation characteristics. From the multiple correlation values, the correlation value that represents the optimum correlation is identified. This technique significantly reduces the gate count of the decoder structure, thus saving chip area and manufacturing costs.

Complementary code decoding by reduced sized circuits

An error correction technique for data communication receivers such as WLAN (Wireless Local Area Network) receivers is provided. The error correction technique is for correcting a frequency and/or phase error in an incoming digitally modulated signal. A constellation manipulator is provided that is adapted to manipulate the phase constellation system of the incoming digitally modulated system by mapping each constellation point of the phase constellation system to a predefined range of phase angles. The predefined range has a width of less than 2&#x3c0;. Further, an error detector is provided that is connected to receive data from the constellation manipulator. The data pertains to the manipulated phase constellation system. The error detector is adapted to evaluate the data to detect the frequency and/or phase error.

Constellation manipulation for frequency/phase error correction

A WLAN (Wireless Local Area Network) receiver with a synchronization unit is provided, wherein the synchronization unit comprises a frequency error correction unit configured to perform a frequency error correction process, a phase error correction unit configured to perform a phase error correction process, a filter circuit capable of applying one of at least two different filter transfer functions, wherein a first one of said at least two different filter transfer functions is a frequency error correction filter transfer function for use in said frequency error correction process and a second one of said at least two different filter transfer functions is a phase error correction filter transfer function for use in said phase error correction process, and a controller unit connected to said filter circuit to select one of said at least two different filter transfer functions.

Circuit sharing for frequency and phase error correction

A wireless local area network receiver is provided that has an interference reduction unit for reducing interchip interference in a received signal that is modulated using a complementary code keying technique such as CCK-11. The interference reduction unit comprises a decision feedback equalizer that has a feedforward filter for reducing precursor interference and a feedback filter for reducing postcursor interference in the received signal. The receiver may perform channel estimation to optimize the filter coefficients during the preambles of the incoming sequence.

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Dresden, Germany

Uwe Eckhardt