Advanced Micro Devices Corporation

Jörg Borowski

Frank Poegel

Uwe Eckhardt

Menno Mennenga

Wolfram Kluge

Eric Sachse

Tilo Ferchland

Michael Schmidt

Thomas Hanusch

Ingo Kühn

Klaus Meyer

Rüdiger Menken

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

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

A technique for performing a frequency error correction process is provided that may be used in receivers of wireless local area network systems. The technique comprises a three-phase process generating a frequency approximation value based on a frequency error estimate, starting a channel estimation process that uses the generated frequency approximation value, refining the generated frequency approximation value, and compensating a frequency error using the refined frequency approximation value. Further, a corresponding integrated circuit chip and an operation method are provided. Using the technique for performing a frequency error correction process may provide high reliability, high precision and improved operation speed.

Frequency error correction in a communication system

A signal pre-processing device particularly in wireless LAN devices is provided that comprises an AGC (Automatic Gain Control) unit, an ADC (Analog-to-Digital Converting) unit and a normalization unit. The AGC unit amplifies a received analog input signal and outputs an amplified analog signal. Further, it automatically controls an amplification gain when amplifying the analog input signal. The ADC unit receives the amplified analog signal, converts it into a digital signal and outputs the digital signal. The normalization unit is receives the digital signal, applies a normalization function to the digital signal and outputs the normalized digital signal. Thus, less precise AGC units can be used, thereby reducing production costs as well as the size and complexity of the AGC unit. Further, shorter circuit development times are obtainable.

Gain control in wireless LAN devices

A WLAN (Wireless Local Area Network) receiver having a synchronization unit is provided. The synchronization unit comprises a first functional unit for performing a first signal processing function, a second functional unit for performing a second signal processing function different from the first signal processing function, and at least one signal processing circuit. In the synchronization unit the first functional unit is operating at least one of the signal processing circuits for performing the first signal processing function, and the second functional unit is arranged for operating the at least one signal processing circuit operated by the first functional unit for performing the second signal processing function. Since the above-described signal processing circuits or modules can be re-used for the antenna diversity unit and the preamble detection unit this results in a smaller number of gates and an improved density of the circuitry.

Shared circuitry for WLAN receiver functional units

A method and system for providing a frequency correction for a spread spectrum communication receiver. In the method and system, a frequency offset is determined by processing successive samples of a despread data signal. A correction sequence is generated from this determined offset and combined with a code-spread received signal prior to despreading. A filter may be included in order to reduce noise in the system.

Digital correction method and system

A synchronization data detecting unit is provided in a communication system for detecting predetermined synchronization data. The synchronization data are sent in a transmission frame in a communication signal of the communication system. The synchronization data include a sequence of identical binary symbols which are transmitted after scrambling. The synchronization detection unit comprises a descrambler for descrambling the received communication and for producing an output data sequence having multi-level signal values. The multi-level signal values of the descrambler output are smoothed in a filter unit. The smoothed signal is compared with a predetermined threshold value. If the smoothed signal exceeds the predefined threshold value, a detection of said synchronized data is indicated.

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Dresden, Germany

Jörg Borowski