Freescale Semiconductor,inc.

Jianqiang Zeng

Kevin B Traylor

Raja Venkatesh Tamma

Steven M Bosze

Khurram Waheed

Kuhurram Waheed

A technique for frame synchronization in a communication system includes performing symbol correlation on received signal samples. A determination is made as to whether a magnitude of the symbol correlation is greater than a first threshold. In response to the magnitude of the symbol correlation being greater than the first threshold, an indication is provided that the received symbol is a valid symbol (e.g., a SYNCP symbol or SYNCM symbol). In response to the magnitude of the symbol correlation being less than the first threshold, an indication is provided that the received symbol is an indeterminate symbol (e.g., an invalid symbol or a SYNCM/2 symbol).

Techniques for time-domain frame synchronization of packets

Methods and systems are disclosed for frequency-domain symbol and frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency components associated with subcarriers within the multi-carrier communication signals. Symbol synchronization is performed in the frequency domain by performing correlation(s) between frequency components of the received signal and frequency-domain synchronization symbol(s). After symbol synchronization, frame synchronization correlation is also performed in the frequency domain between frequency components of the received signal and frequency-domain synchronization symbol(s). The disclosed embodiments are particularly useful for symbol and frame synchronization in multi-carrier received signals for power line communication (PLC) systems and/or other harsh noisy communication environments.

Frequency-domain symbol and frame synchronization in multi-carrier systems

Methods and systems are disclosed for frequency-domain frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency domain components associated with subcarriers within the multi-carrier communication signals. A sliding-window correlation (e.g., two-dimensional sliding window) is applied to the received symbols represented in the frequency domain to detect frame boundaries for multi-carrier signals. The sliding-window frame synchronization can be applied by itself or can be applied in combination with one or more additional frame synchronization stages. The disclosed embodiments are particularly useful for frame synchronization of multi-carrier signals in PLC (power line communication) systems.

Frequency-domain frame synchronization in multi-carrier systems

Methods and systems are disclosed for frequency-domain amplitude normalization for symbol correlation in multi-carrier communication systems. Digital samples associated with input signals received from a communication medium are processed using a Fast Fourier Transform (FFT) to generate complex frequency components. Each complex frequency component is normalized with respect to its amplitude, and the frequency-domain, amplitude-normalized frequency components are multiplied with frequency components for reference symbol(s) to generate frequency-domain correlation values. These frequency-domain correlation values are analyzed to determine if a correlation exists between the amplitude-normalized frequency components and the predetermined reference frequency components. A correlation detection output is then generated that indicates whether or not a symbol synchronization was achieved. The disclosed embodiments are particularly useful for symbol correlation in received signals for power line communication (PLC) systems.

Frequency-domain amplitude normalization for symbol correlation in multi-carrier systems

A transmitter and method for processing a digitally modulated communication signal, which may reduce peak-to-average-power-ratio (PAPR) while maintaining acceptable error rates is disclosed. After subcarrier mapping, a first digital representation of the signal is upsampled into a second digital representation, which is transformed into a first time domain representation. Samples whose magnitudes exceed a magnitude limit are limited to that limit to produce a second time domain representation. The second time domain representation is transformed to a third frequency domain representation, which is downsampled into a fourth frequency domain representation. In addition to the in-band subcarriers, some out-of-band subcarriers adjacent to the frequency band are preserved while the remaining out-of-band subcarriers are eliminated to produce a fifth frequency domain representation. The fifth frequency domain representation is then transformed to a third time domain representation, which is converted to an analog signal to be transmitted.

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Austin, TX, United States of America

Jianqiang Zeng