Realtek Semiconductor Inc.

Lucent Technologies Inc.

Wionics Technologies, Inc.

Turgut Sefket Aytur

Stephan Ten Brink

Ravishankar H Mahadevappa

Ran Yan

Venkatesh Rajendran

Nathan R Belk

Ping-Wen Ong

Saurabh Garg

Batuhan Okur

Frederic Battaglia

Ran-Hong Yan

Behzad Razavi

Han-Chang Kang

Feng Shi

Fred Battaglia

Mustafa Altintas

Systems are disclosed that utilize AC-coupled filtering to reduce DC offset, with aspects dynamically correcting instantaneous DC offset generated from the AC-coupled filtering. A DC offset correction circuit for an radio frequency (rf) receiver, comprising a switchable high pass filter configured to receive a signal, the switchable high pass filter including a plurality of high pass filters connected in parallel, wherein at least one of the plurality of high pass filters has a tunable corner frequency.

Dynamic AC-coupled DC offset correction

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

Methods and systems that utilize AC-coupled filtering to reduce DC offset, with aspects dynamically correcting instantaneous DC offset generated from the AC-coupled filtering. A DC offset correction circuit for an radio frequency (rf) receiver comprises a switchable high pass filter receiving a downconverted rf signal. The switchable high pass filter has N selectable corner frequencies, where N is greater than two.

Certified Wireless USB 1.0 (CWUSB) defines two different types of association: cable association and numeric association. In the numeric association, the CWUSB host and device use a specific protocol to exchange the security information. At final stage of this information exchange, both host and device need to display a number asking user's feedback. Once this is done, both host and device will be able to generate the connection key as the shared secret for the following secured communication. One problem of this numeric association method is that device needs to be able to display the numbers. For certain class of device that has capability to display an image, there is a natural way to add this function to them. A method for this class of devices is described. Another kind of association, which is not defined in the CWUSB 1.0, is manual association. User needs only to manually type in the Connection Key coming from the CWUSB device. There are many ways to delivery the key, but it is very easy for device that can display an image.

Association using USB video adapter

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 method and system for detecting the presence of narrowband transmitters utilizing frequencies also utilized by wider band communication systems. In some embodiments an ultrawideband transceiver detects signals at specific frequencies within a spectrum of frequencies, and analyzes the signals to determine if the signals indicate transmissions by a narrowband transmitter in a narrowband communication system. In further embodiments transmission circuitry reduces signal components at frequencies occupied by the narrowband transmitters.

Detect-and-avoid method and architecture for ultra-wideband system

Universal Serial Bus (USB) is a Master/Salve or Host/Device system in which there is only one host and one or more devices connected by cables to the host. To connect a USB device to a different host controller (say another PC), the user unplugs the USB cable and establishes the connection physically by plugging the cable into the new host controller interface. Certified Wireless USB (CWUSB), a logical extension to the USB, preserves the USB connection model, except that the link between the host and the device is now using a wireless technology. A wireless device is usually connected to only one wireless host at a given point of time, even though several wireless hosts may be co-located in the same physical neighborhood. The connection between the wireless host and device is initiated by the device. A device usually selects a wireless host from a stored set of known hosts that have established a trusted relationship with the device. If more than one wireless host is operating in the same neighborhood, there is no well known established procedure for the device to select a particular wireless host to establish a connection.

CWUSB host management system

Certified Wireless USB 1.0 defines two different types of association: cable association and numeric association. In order to implementation these two association methods, the CWUSB device needs to have either upstream USB connector (for cable association) or display capability (for numeric association). These extra requirements make the CWUSB device bulkier (one more USB connector) and/or more expensive (extra display components). For cheap and simple CWUSB devices, we need a simpler association method that is easy and cheap to implement. In a pre-packaged total solution, which includes a host and one or more device(s), we can use pre-association to smooth the user experience. The host and device(s) are pre-associated. When an end user starts to use this solution, they do not need to worry about the association at all.

Pre-association for CWUSB

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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Plattsburg, NY, United States of America

Turgut Sefket Aytur