Pei C Chen

US Patent:

7027519, Apr 11, 2006

Filed:

Feb 28, 2001

Appl. No.:

09/796124

Inventors:

Jay Bao - Vista CA, US
Pei Chen - San Diego CA, US
Hisashi Kobayashi - New Brunswick NJ, US

Assignee:

Mitsubishi Electric Research Laboratories, Inc. - Cambridge MA

International Classification:

H04L 23/02

US Classification:

375260, 375262, 375341

Abstract:

In orthogonal frequency division multiplexing systems, iterative maximum likelihood channel estimation and signal detection is preformed. The channel estimation gives the maximum likelihood estimates of time domain channel parameters. A cost function is defined. An iterative process estimates a joint channel impulse response and a transmitted signal that minimize the cost function, and thus solves the channel estimation and signal detection problem jointly without having specific knowledge of the channel.

US Patent:

7512863, Mar 31, 2009

Filed:

Oct 12, 2005

Appl. No.:

11/249293

Inventors:

Pei Chen - San Diego CA, US
Ahmad Jalali - Rancho Santa Fe CA, US

Assignee:

Qualcomm Corporation - San Diego CA

International Classification:

H03M 13/00

US Classification:

714755

Abstract:

At least one aspect of the invention provides a turbo encoder having parallel first and second constituent encoders and an interleaver coupled as an input to the second constituent encoder to provide a permutated version of the binary data input to the first constituent encoder to achieve a low frame error rate. The interleaver is configured to parse the binary data input into an input block, determine a permutation vector, and rearrange the order of the binary data in the input block according to a set of predetermined permutation equations. The rearranged binary data in the information block is then passed to the second constituent encoder to improve the distance spectrum of the transmitted redundant data.

US Patent:

7558576, Jul 7, 2009

Filed:

Sep 20, 2005

Appl. No.:

11/231395

Inventors:

Pei Chen - San Diego CA, US
Ivan Jesus Fernandez-Corbaton - Nuremberg, DE

Assignee:

Qualcomm Incorporated - San Diego CA

International Classification:

H04W 36/32
H04B 1/12

US Classification:

455441, 455504, 455 631, 455 6716, 455230

Abstract:

At least one embodiment of the invention provides an automated frequency offset compensation method, system, and apparatus that improves throughput between one or more wireless communication devices by compensating for frequency offsets caused by a Doppler effect. In particular, one implementation estimates the frequency offset and uses this to compensate the carrier signal power to interference power ratio (C/I) when the transmitting and receiving devices are moving relative to each other such that a Doppler effect creates a frequency offset in the perceived frequency of the received carrier signal.

US Patent:

7929646, Apr 19, 2011

Filed:

May 25, 2006

Appl. No.:

11/441653

Inventors:

Pei Chen - San Diego CA, US
Ivan Jesus Fernandez-Corbaton - Nuremberg, DE
Jordi de los Pinos Pont - San Diego CA, US

Assignee:

Qualcomm Incorporated - San Diego CA

International Classification:

H04L 27/06

US Classification:

375341, 375253, 375262, 375265

Abstract:

A MAP decoder, or a turbo decoder having constituted MAP decoders, is configured with bi-directional sliding windows. A sliding window architecture is applied to the forward state metric (FSM) calculation of an encoded data block having a trellis with N time-steps. The data block is divided into smaller sub-blocks and a forward recursion of two or more of the sub-blocks are performed in parallel to obtain FSMs. Each sub-block overlaps with a previous sub-block by k time-steps, where k is an integer value greater than zero. This provides a good approximation of the FSMs at time-step k+t of the sub-block. The FSMs associated with the first k time steps of each sub-block, other than the first sub-block, are discarded. A reverse recursion of each sub-block is also performed to obtain reverse state metrics (RSM) for the sub-block. Likelihood ratios are then calculated based on the FSMs and RSMs.

US Patent:

8503353, Aug 6, 2013

Filed:

Nov 5, 2010

Appl. No.:

12/940361

Inventors:

Pei Chen - San Diego CA, US
Bin Tian - San Diego CA, US

Assignee:

QUALCOMM Incorporated - San Diego CA

International Classification:

H04B 7/204
H04B 7/185

US Classification:

370319, 370318

Abstract:

Arrangements are presented for adjusting a power level and data rate at an access terminal. The access terminal may include a transmitter module configured to transmit data packets to a gateway. The access terminal may include a receiver module configured to receive control data generated at the gateway. The access terminal may also include a control module. The control module may evaluate the received control data. The control module may increase a transmit power level for data packets to be transmitted from the transmitter module when a first set of conditions is not satisfied. In the first set of conditions, the control data may include a first command. The control module may increase a data rate for data packets to be transmitted from the transmitter module when a second set of conditions is satisfied. In the second set of conditions, the control data may include a second command.