Ashok Mantravadi

US Patent:

7660275, Feb 9, 2010

Filed:

Oct 18, 2004

Appl. No.:

10/968787

Inventors:

Rajiv Vijayan - San Diego CA, US
Fuyun Ling - San Diego CA, US
Gordon Kent Walker - Poway CA, US
Ramaswamy Murali - San Diego CA, US
Ashok Mantravadi - San Diego CA, US
Anand Subramaniam - La Jolla CA, US
Krishnamurthy Viswanathan, legal representative - La Jolla CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04H 20/71

US Classification:

370312, 370344, 370347, 370208, 455503

Abstract:

To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.

US Patent:

7701917, Apr 20, 2010

Filed:

Feb 5, 2004

Appl. No.:

10/773646

Inventors:

Ashok Mantravadi - San Diego CA, US
Aamod Khandekar - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04J 1/00
H04J 3/00
H04B 7/212

US Classification:

370343, 370345, 370347

Abstract:

To recover multiple data streams transmitted simultaneously, a first channel estimate is derived for a wireless channel based on received pilot symbols. Detection is performed on received data symbols using the first channel estimate to obtain detected symbols for a first data stream. These detected symbols are decoded to obtain a decoded first data stream, which is re-encoded to obtain remodulated symbols. A second channel estimate is derived based on the remodulated symbols. The first and second channel estimates are combined to obtain a third channel estimate having higher quality. Interference due to the first data stream is estimated using the third channel estimate and canceled from the received data symbols. Detection is performed on interference-canceled symbols using the third channel estimate to obtain detected symbols for a second data stream. These detected symbols are further decoded to obtain a decoded second data stream.

US Patent:

7706288, Apr 27, 2010

Filed:

Feb 21, 2006

Appl. No.:

11/359148

Inventors:

Linbo Li - San Diego CA, US
Ashok Mantravadi - San Diego CA, US
Fuyun Ling - San Diego CA, US
Raghuraman Krishnamoorthi - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04L 12/26
H04W 4/00
H04W 36/00

US Classification:

370241, 370331, 455436

Abstract:

Systems and methodologies are described that facilitate monitoring RF channels in a wireless communication environment to determine whether one or more channels comprise a forward-link-only (FLO) signal. A receiver can receive a first RF channel with a FLO signal and can monitor other RF channels for FLO signals. Upon a determination that a monitored RF channel comprises a FLO signal, the receiver can switch between the first RF channel and the monitored RF channel to facilitate providing seamless reception of the FLO signal, which can be superframe synchronized between RF channels. FLO signal detection can be performed using one or more of a wide-area identification channel energy detection protocol and a wide-area overhead information symbol decoding error detection protocol.

US Patent:

7720027, May 18, 2010

Filed:

Jul 27, 2006

Appl. No.:

11/495480

Inventors:

Fuyun Ling - San Diego CA, US
Murali Ramaswamy Chari - San Diego CA, US
Rajiv Vijayan - San Diego CA, US
Ashok Mantravadi - San Diego CA, US
Alok Kumar Gupta - Encinitas CA, US
Krishna Kiran Mukkavilli - San Diego CA, US
Michael Mao Wang - San Diego CA, US
Bojan Vrcelj - San Diego CA, US
Bruce Collins - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04W 4/00

US Classification:

370328, 709236, 455 9, 4555501, 455445, 455424, 375260, 370312

Abstract:

Systems and methods are provided for processing forward link only (FLO) signals. A device receives a FLO signal, processes a TDM pilot comprising a TDM Pilot , a TDM Pilot , a WIC, a LIC, a Transition Pilot Channel, and a Positioning Pilot, from the FLO signal, processes an overhead information symbol (OIS) comprising a wide-area OIS and a local-area OIS, from the FLO signal, processes an FDM pilot comprising a wide-area FDM pilot and a local-area FDM pilot, from the FLO signal; and processes data comprising wide-area data and local-area data, from the FLO signal.

US Patent:

7720185, May 18, 2010

Filed:

Nov 6, 2006

Appl. No.:

11/557035

Inventors:

Bojan Vrcelj - San Diego CA, US
Ashok Mantravadi - San Diego CA, US
Fuyun Ling - San Diego CA, US
Linbo Li - San Diego CA, US
Raghuraman Krishnamoorthi - San Diego CA, US
Murali Ramaswamy Chari - San Diego CA, US
Vinay Murthy - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04B 1/10

US Classification:

375349, 375350

Abstract:

The disclosure is directed to a receiver. The receiver includes an interference canceller configured to filter digital samples produced from a modulated signal transmitted over a wireless channel, and a digital variable gain amplifier (DVGA) configured to amplify the filtered digital samples.

US Patent:

7724838, May 25, 2010

Filed:

Mar 1, 2004

Appl. No.:

10/791314

Inventors:

Ashok Mantravadi - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04L 27/00

US Classification:

375295, 375260, 375261, 375263, 375267, 375299

Abstract:

Techniques are provided for performing hierarchical coding in a multi-antenna communication system (e. g. , a SIMO, MISO, or MIMO system). At a transmitter, a base stream and an enhancement stream are coded and modulated separately to obtain first and second data symbol streams, respectively. The first data symbol stream is processed in accordance with a first spatial processing scheme (e. g. , a transmit diversity or a spatial multiplexing scheme) to obtain a first set of symbol substreams. The second data symbol stream is processed in accordance with a second spatial processing scheme (e. g. , transmit diversity or spatial multiplexing) to obtain a second set of symbol substreams. The first set of symbol substreams is combined (e. g. , using time division multiplexing or superposition) with the second set of symbol substreams to obtain multiple transmit symbol streams for transmission from multiple transmit antennas. A receiver performs complementary processing to recover the base stream and enhancement stream.

US Patent:

7782806, Aug 24, 2010

Filed:

Mar 9, 2006

Appl. No.:

11/373607

Inventors:

Bojan Vrcelj - San Diego CA, US
Ashok Mantravadi - San Diego CA, US
Fuyun Ling - San Diego CA, US
Krishna Kiran Mukkavilli - San Diego CA, US
Raghuraman Krishnamoorthi - San Diego CA, US
Michael Mao Wang - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04B 7/00

US Classification:

370310, 370315

Abstract:

Systems and methods are provided for channel estimation and timing synchronization in a wireless network. In an embodiment, a method is provided for time synchronization at a wireless receiver. The method includes decoding at least one TDM pilot symbol located at a transition between wide and local waveforms and processing the TDM pilot symbol to perform time synchronization for a wireless receiver. Methods for channel estimation at a wireless receiver are also provided. This includes decoding at least one TDM pilot symbol and receiving the TDM pilot symbol from an OFDM broadcast to facilitate channel estimation for a wireless receiver.

US Patent:

7787517, Aug 31, 2010

Filed:

Jan 28, 2005

Appl. No.:

11/046121

Inventors:

Ashok Mantravadi - San Diego CA, US
Anand D. Subramaniam - La Jolla CA, US
Krishnamurthy Viswanathan, legal representative - La Jolla CA, US
Dhananjay Ashok Gore - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04L 27/30

US Classification:

375141, 375146, 375260, 370203, 370331, 455436, 455442, 455443, 455450

Abstract:

Accordingly, a method and apparatus are provided to convert received content into a first stream and a second stream, to transmit said first stream using a first tone and to transmit said second stream using an orthogonal scheme. A layering scheme is used to transmit the base stream covering a smaller area and an enhanced stream is used to cover a large utilizing orthogonal scheme.