Realtek Semiconductor Inc.

Ran Yan

Turgut Sefket Aytur

Stephan Ten Brink

Ravishankar H Mahadevappa

Behzad Razavi

Han-Chang Kang

Venkatesh Rajendran

Feng Shi

Mustafa Altintas

An apparatus for and a method of performing packet detection in a receiver is provided. The apparatus is configured to determine a measure of a correlation between information of one or more received symbols and synchronization information. The apparatus is also configured to determine a measure of an energy value of one or more of the received symbols. The apparatus is also configured to determine if a packet has been detected based on the measure of the correlation and the measure of the energy value of the one or more received symbols.

Packet detection

An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Automatic gain control for frequency-hopped OFDM

A direct conversion ultrawideband transceiver employing three phase locked loops (PLLs). The PLLs are preferably fixed-frequency PLLs that operate continuously, at different frequencies, with a selected frequency determined by selecting the output of one of the three PLLs. The use of three PLLs is suitable for use in a communication system employing frequency hopping across three bands or sub-bands.

CMOS transceiver for communication system

A receiver including a channel estimation function in which an initial channel estimate is filtered to increase receiver operation, particularly when the receiver may only have a limited number of channel estimation symbols with which to form the channel estimate. In some embodiments the filtering is performed by transforming the initial channel estimate to the time domain, zeroing some of the samples to filter the time domain channel estimate, and transforming the filtered time domain channel estimate to the frequency domain for use in channel compensation.

Channel estimation

Systems and methods for packet detection for frequency hopping networks. Multiple receiver chains are set to different frequencies to check for packets at the different frequencies, at least until receipt of a preamble sequence in a packet is received. After detection of a packet at least some of the receiver chains are used to process received signals according to a frequency hopping pattern.

Packet detection in time/frequency hopped wireless communication systems

Pairs of parallel Viterbi decoders use windowed block data for decoding data at rates above 320 Mbps. Memory banks of the deinterleavers feeding the decoders operate such that some are receiving data while others are sending data to the decoders. Parallel input streams to every pair of decoders overlap for several traceback lengths of the decoder causing data input to a first decoder at the end of an input stream to be the same as the data input to a second decoder of the same pair at the beginning of an input stream. Then, the first decoder is able to post-synchronize its path metric with the second decoder and the second decoder is able to pre-synchronize its path metric with the first. Either, the deinterleaver data length is an integer multiple of the traceback length or the data input to only the first block of the first interleaver is padded.

Deinterleaver and dual-viterbi decoder architecture

Frame synchronization methods and systems suited for packet communications systems, and particularly time frequency hopping packet communication systems, are disclosed. Frame synchronization is performed by performing a first correlation on information of received symbols and performing a second correlation on results of the first correlation. In systems with repeating synchronization information modulated by a cover sequence, the results of the second correlation may be used to determine symbol numbering of symbols in a packet.

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Holmdel, NJ, United States of America

Ran Yan