Subrahmanya, CA
Paravathanathan Subrahmanya, Sunnyvale, CA US
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20100158175 | METHOD AND APPARATUS FOR FILTERING NOISY ESTIMATES TO REDUCE ESTIMATION ERRORS - Techniques for filtering noisy estimates to reduce estimation errors are described. A sequence of input values (e.g., for an initial channel impulse response estimate (CIRE)) is filtered with an infinite impulse response (IIR) filter having at least one coefficient to obtain a sequence of output values (e.g., for a filtered CIRE). The coefficient(s) are updated based on the sequence of input values with an adaptive filter, a bank of prediction filters, or a normalized variation technique. To update the coefficient(s) with the adaptive filter, a sequence of predicted values is derived based on the sequence of input values. Prediction errors between the sequence of predicted values and the sequence of input values are determined and filtered to obtain filtered prediction errors. The coefficient(s) of the IIR filter are then updated based on the prediction errors and the filtered prediction errors. | 06-24-2010 |
20100273427 | METHOD AND APPARATUS FOR FILTERING NOISY ESTIMATES TO REDUCE ESTIMATION ERRORS - Techniques for filtering noisy estimates to reduce estimation errors are described. A sequence of input values (e.g., for an initial channel impulse response estimate (CIRE)) is filtered with an infinite impulse response (IIR) filter having at least one coefficient to obtain a sequence of output values (e.g., for a filtered CIRE). The coefficient(s) are updated based on the sequence of input values with an adaptive filter, a bank of prediction filters, or a normalized variation technique. To update the coefficient(s) with the adaptive filter, a sequence of predicted values is derived based on the sequence of input values. Prediction errors between the sequence of predicted values and the sequence of input values are determined and filtered to obtain filtered prediction errors. The coefficient(s) of the IIR filter are then updated based on the prediction errors and the filtered prediction errors. | 10-28-2010 |
Parvathanathan Subrahmanya, San Diego, CA US
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20100260155 | METHOD AND APPARATUS FOR TIME-ALIGNING TRANSMISSIONS FROM MULTIPLE BASE STATIONS IN A CDMA COMMUNICATION SYSTEM - Schemes to time-align transmissions from multiple base stations to a terminal. To achieve time-alignment, differences between the arrival times of transmissions from the base stations, as observed at the terminal, are determined and provided to the system and used to adjust the timing at the base stations such that terminal-specific radio frames arrive at the terminal within a particular time window. In one scheme, a time difference between two base stations is partitioned into a frame-level time difference and a chip-level time difference. Whenever requested to perform and report time difference measurements, the terminal measures the chip-level timing for each candidate base station relative to a reference base station. Additionally, the terminal also measures the frame-level timing and includes this information in the time difference measurement only if required. Otherwise, the terminal sets the frame-level part to a predetermined value (e.g., zero). | 10-14-2010 |
20100322126 | APPARATUS AND METHODS FOR LOW POWER SENSING OF COMMUNICATION ACCESS TECHNOLOGIES - Apparatus and methods for low power sensing of wireless access technologies are disclosed. In particular, a mobile wireless device, such as an access terminal, may utilize a lower power circuitry portion that operates at a lower power than active circuitry, such as a primary transceiver. The lower power circuitry portion includes a configurable searcher that is capable of sensing if signals of one or more various wireless access technologies are present. When the wireless device utilizes sleep or idle modes for power savings, use of the lower power sensing circuitry to sense the presence of wireless access technologies, rather than using an awoken higher power primary transceiver for sensing, affords increased power savings. An added ability of the lower power circuitry to be put into sleep or idles modes achieves even greater power savings. | 12-23-2010 |
20110103431 | METHODS AND SYSTEMS FOR INTERFERENCE CANCELLATION IN MULTI-MODE COEXISTENCE MODEMS - Certain embodiments of the present disclosure support techniques for interference cancellation in a multi-mode wireless modem that supports coexistence of different radio technologies. | 05-05-2011 |
20110105037 | METHODS AND SYSTEMS FOR INTERFERENCE CANCELLATION IN MULTI-MODE COEXISTENCE MODEMS - Certain embodiments of the present disclosure support techniques for interference cancellation in a multi-mode wireless modem that supports coexistence of different radio technologies. | 05-05-2011 |
20110149757 | METHOD AND APPARATUS FOR FACILITATING CELL DETECTION USING ADDITIONAL PHYSICAL CHANNELS IN A WIRELESS COMMUNICATION SYSTEM - The described apparatus and methods may include a receiver configured to receive a signal, the signal being a combination of physical channel signals that each correspond to a different one of a plurality of physical channels, and a controller configured to capture signal energy from at least two of the physical channel signals, and detect a cell based on the captured signal energy. | 06-23-2011 |
20120257657 | DYNAMIC ELECTROMAGNETIC RADIATION EMISSION CONTROL IN WIRELESS COMMUNICATION DEVICES - Methods and apparatus for active and passive dynamic electromagnetic radiation emission control in wireless devices by limiting transmit power in individual devices is disclosed. In various embodiments, electromagnetic radiation emissions from wireless devices are dynamically controlled using variable transmit power limits acquired through the use of RF ID/NFC tags that indicate transmit power limits, where such power limiting tags are embedded in clothing, furniture, etc., communication of transmit power limits over Bluetooth or other short range technologies, location-based transmit power limits, user input transmit power limits. Controlling the transmit power of mobiles as well as femtocells/access points for the purpose of minimizing SAR using variable transmit power limits is detailed. | 10-11-2012 |
Parvathanathan Subrahmanya, Santa Clara, CA US
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20100309900 | SEARCHER FOR MULTIPLE ORTHOGONAL CHANNELS WITH KNOWN DATA- WCDMA STEP2 SEARCH - A circuit and algorithm are disclosed for a step2 search of a three step search of synchronization channels in a W-CDMA system. A mobile terminal of the CDMA system includes an RF downconverter for receiving I and Q signals. A searcher, responsive to the I and Q signals, includes a first correlator for correlating the I and Q signals with a primary synchronization code on a primary synchronization channel, and a second correlator for correlating I and Q signals with a secondary synchronization code on a secondary synchronization channel. The correlated I and Q signals are added for each of the secondary synchronization codes. An energy calculator and a maximum energy detector use the correlated I and Q signals of both the primary and secondary synchronization channels to detect the most likely scrambling code group of secondary synchronization codes. | 12-09-2010 |
20120224498 | BAYESIAN PLATFORM FOR CHANNEL ESTIMATION - Certain aspects of the present disclosure propose a method for estimating a channel utilizing Sparse Bayesian Learning (SBL) algorithm. The proposed method employs a Basis expansion (e.g., polynomial) channel model, and iteratively performs SBL algorithm to adjust parameters of the channel model. | 09-06-2012 |
Parvathanathan Subrahmanya, San Jose, CA US
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20100150212 | RAKE RECEIVER FINGER ASSIGNMENT BASED ON SIGNAL PATH CONCENTRATION - A rake receiver finger assignor is configured to assign a rake receiver finger to a time offset between identified signal path time offsets in accordance with a concentration of identified signal paths from a transmitter to a rake receiver. In accordance with the exemplary embodiment, a number of identified signal paths having time offsets within a time window are observed to determine the concentration of signal paths identified by a path searcher. If the number of identified signal paths indicates a concentrated distribution of signal paths such as during a fat path condition, at least one rake finger is assigned between at a time offset between two identified signal paths. | 06-17-2010 |