Abstract: A data communications technique is provided that may be used in WLAN (Wireless Local Area Network) receivers. Data signals modulated in accordance with one of at least two different modulation schemes are received. The front end of the device has an analog and a digital part, and the digital front end includes a first and a second signal processing branch for processing received data signals modulated in accordance with different modulation schemes. The first and second processing branches have low-IF (Intermediate Frequency) topologies. There is further provided a corresponding integrated circuit chip and a method of processing received data signals.

Abstract: 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.

Abstract: A phase error corrector circuit and method are disclosed. In one embodiment, a phase error corrector circuit delays a PSK modulated signal and multiplies the delayed PSK modulated signal by the PSK modulated signal in order to generate a forward phase correction signal. The input signal is then mixed with the forward phase correction signal. In another embodiment, a phase error corrector circuit calculates a forward phase offset of a complex PSK modulated signal. The complex PSK modulated signal is phase shifted in a mixer by a phase difference offset in order to generate a phase corrected signal. A backward phase correction means calculates a backward phase offset based on the phase corrected signal. A subtractor subtracts the forward phase offset from the backward phase offset for outputting a difference phase offset to the mixer.

Abstract: 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&pgr;. Further, an error detector is provided that is connected to receive data from the constellation manipulator. The data pertain to the manipulated phase constellation system. The error detector is adapted to evaluate the data to detect the frequency and/or phase error.

Abstract: 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.

Abstract: A phase error correction technique in receivers such as WLAN receivers is provided. Such receivers comprise a phase error correction unit connected to receive an input signal having a phase error and adapted to generate an output signal having a corrected phase error. Further, the receiver comprises a despreader which is adapted to despread a data signal. The despreader is connected to the phase error correction unit to provide the despread data signal to the phase error correction unit. The phase error correction unit is arranged for correcting the phase error dependent on the despread data signal. The despreader may be a Barker matched filter or a CCK matched filter, and there may be provided a multiplexer for selecting one of the filters.

Abstract: A phase error correction technique in data communication receivers such as WLAN (Wireless Local Area Network) receivers is provided. A signal having a phase error is received, and a phase error correction mechanism having a loop structure is operated on the input signal to correct the phase error. The corrected signal still has a residual phase error. The residual phase error is then compensated taking into account a loop time delay of the loop structure. Further, a phase change rate may be taken into account, and a smoothing process may additionally be performed.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A data communications device and method is provided that apply an LMS (Least Mean Square) channel estimation. A coefficient calculation unit generates a signal that represents at least one channel coefficient that is indicative of a property of the channel such as its finite impulse response. Further, an error calculation unit generates an error signal. Dependent on the error signal, the channel coefficients are updated by performing the LMS algorithm using a step size of two to a negative integer power. This allows for a simple, less complex implementation, and may be applied in a wireless local area network receiver for adjusting filter coefficients.