Silicon Laboratories Inc.

Redpine Signals, Inc.

Sriram Mudulodu

Venkat Mattela

Subba Reddy Kallam

Partha Sarathy Murali

Logeshwaran Vijayan

Manoj Kumar Medam

Ajay Mantha

Suryanarayana Varma Nallaparaju

Suchin Gupta

Divyaxi Rudani

The present invention relates to a method and apparatus for reducing power consumption in a receiver of a time slotted communication system. An RF front end has power applied after the start of a preamble or after the start of a header, or upon the start of a packet payload based on connection status, signal level, and interference level. Where the signal level is constant, the communication system is in a connected state, and the interference level is low, the system bypasses packet header destination address matching, or optionally, uses only the least significant bits of the header destination address for matching purposes.

Conditional automatic gain control on single station piconet for bluetooth receiver based on connection state

In one aspect, a receiver includes a digital processor having a digital signal processing path that comprises: a packet detector to detect a packet; a channel profile circuit coupled to the packet detector to determine a channel profile of a channel via which the packet is received; a fast Fourier transform (FFT) engine to convert time domain samples of the packet to frequency domain samples; and a plurality of smoothing filters. The receiver further includes a controller coupled to the channel profile circuit to select one of the plurality of smoothing filters to couple into the digital signal processing path based at least in part on the channel profile.

Methods and system for improving channel estimation in a receiver

Conditional automatic gain control with partial address detection for Bluetooth receiver based on connection state

A bitstream modifier is operative on a packet which uses repetition coding. The bitstream modifier increases randomness of the data in a deterministic manner such that spectral spurs from repetition coding are greatly reduced, thereby providing greater available transmit power. In another example of the invention, baseband samples of a header and/or payload for a Bluetooth packet are modified by a canonical sequence with a low slew rate for data such that the variations in frequency may be tracked by a receiver and the transmitted spectral spurs reduced.

Apparatus and method to reduce spectral peaks in Bluetooth communications

A Bluetooth receiver has an RF front end which has a gain control input, the RF front end converting wireless packets into a baseband signal which is coupled to the input of an analog to digital converter (ADC). A clock generator provides a clock coupled to the ADC, and an AGC processor performs an AGC process to provide a gain which places the baseband symbols in a range that is less than 90% of the input dynamic range of the ADC. When in a connected state, the clock generator provides a clock which is slower than is required to complete the AGC process during a preamble interval, and the AGC process uses a few initial bits of the address field. The remaining bits of the address field is compared with the corresponding address bits of the receiver to determine whether to receive the packet.

Variable rate sampling in a Bluetooth receiver using connection state

A receiver for OFDM subcarriers has a first mode and a second mode. In the first mode, a tunable system clock is output at a nominal frequency, and in the second mode, the tunable system clock is offset so that a harmonic of the tunable system clock coincides with a particular OFDM subcarrier. The tunable system clock is coupled to a programmable modem PLL clock generator which generates clocks for an A/D converter coupled to a baseband processor which is also coupled to the programmable modem PLL clock generator. The programmable modem PLL clock generator is programmed to maintain a constant output frequency of each output in the first mode and the second mode.

System clock spur reduction in OFDM receiver

In one aspect, a radio device comprises: an analog front end (AFE) circuit to receive and process an incoming radio frequency (RF) signal comprising a packet; an analog-to-digital converter (ADC) coupled to the AFE circuit to receive and digitize the processed incoming RF signal into a digital signal; a detector coupled to the ADC to detect a carrier frequency offset (CFO) in the digital signal based at least in part on a preamble of the packet; and a controller coupled to the detector. The controller may generate a compensation value for the CFO based on the detected CFO and cause one or more components of the radio device to compensate for the CFO using the compensation value.

System, apparatus and method for acquisition of signals in wireless systems with adverse oscillator variations

A wireless local area network (WLAN) station receiver has a center frequency offset (CFO) estimator and an CFO table with an association between a CFO value from a recently received access point packet for which the station is associated according to 802.11. The receiver performs a comparison between the CFO estimate of the received packet and the CFO value from the CFO database, and powers the receiver down if the comparison exceeds a threshold. The threshold may be an absolute value in parts per million, or may include a time drift compensation component.

WLAN receiver early power down based on center frequency offset detection

Variable rate sampling in a bluetooth receiver using connection status

Delayed preamble detection for Bluetooth&#xae; receiver based on interferer metrics

Variable rate sampling for AGC in a bluetooth receiver using connection state and access address field

A code decompression engine reads compressed code from a memory containing a series of code parts and a dictionary part. The code parts each have a bit indicating compressed or uncompressed. When the code part is compressed, it has a value indicating the number of segments, followed by the segments, followed by an index into the dictionary part. The decompressed instruction is the dictionary value specified by the index, which is modified by the segments. Each segment describes the modification to the dictionary part specified by the index by a mask type, a mask offset, and a mask.

Decompression engine for executable microcontroller code

An apparatus and method for encrypting messages from a first node splits the message into a plurality of message units, each of which is encrypted. The encrypted message units are split into path units, each of which is directed to a different route path to a destination node. At the destination node, the path units are received and reassembled into encrypted message units, which are decrypted into message fragments and concatenated to form a message corresponding to the original one sent.

System and method for secure communication in a network

A power saving receiver has a controller which is operative to remove power from the receiver when a threshold is exceeded during reception of a packet. The threshold level is formed by comparison of any of: signal energy of unoccupied subcarriers less the signal energy in occupied subcarriers; signal energy in a first range of occupied subcarriers compared to signal energy in a different range of occupied subcarriers; error vector magnitude from a first set of subcarriers to a second set of subcarriers in a different spectral region of the channel; cyclic prefix cross-correlation, or common phase error increase.

Same-channel interference detection and early receiver powerdown for OFDM signal processor

The present invention relates to a method and system of locating a wireless device using received signal strengths. The method comprising: determining a plurality of multiple sets of transmit beamforming weights corresponding to a plurality of access points (APs) associated with a plurality of time slots; transmitting a signal using said each of said plurality of multiple sets of transmit beamforming weights associated with said plurality of time slots by said each access point (AP) of said plurality of access points (APs); and generating a plurality of received signal strengths corresponding to said plurality of time slots associated with said each of said plurality of multiple sets of transmit beamforming weights by said each access point (AP) of said plurality of access points (APs) at any location.

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Hyderabad Telangana, India

Sriram Mudulodu