Li Tien Chang

US Patent:

6501785, Dec 31, 2002

Filed:

Dec 28, 1999

Appl. No.:

09/472784

Inventors:

Li Fung Chang - Holmdel NJ
Kapil K. Chawla - Middletown NJ
Justin C. Chuang - Holmdel NJ
Zoran Kostic - Holmdel NJ
Nelson Sollenberger - Tinton Falls NJ
Xiaoxin Qiu - Bridgewater NJ

Assignee:

ATT Corp. - New York NY

International Classification:

H04J 1306

US Classification:

375133, 455452

Abstract:

This invention provides a dynamic frequency hopping system that utilizes information from multiple base stations. The system assigns frequency hopping patterns based on current interference and traffic environments to avoid interference thus gaining the benefits of interference averaging and interference avoidance. The system imposes less stringent measurement requirements on terminals (wireless mobile devices) because many measurement requirements are replaced by generating estimates based on measurement data received from other base stations within a base station neighborhood. The system may continuously verify that the frequency hopping patterns assigned to the links of the system optimizes system performance. The system compares system performance of possible frequency hopping patterns against currently assigned frequency hopping pattern to optimize system performance. When a request for a link is received, a similar process as above is performed where the request is granted/denied/delayed based on system optimization requirements.

US Patent:

6532225, Mar 11, 2003

Filed:

Jul 27, 1999

Appl. No.:

09/361572

Inventors:

Li Fung Chang - Holmdel NJ
Kapil K. Chawla - Middletown NJ
Justin C. Chuang - Holmdel NJ
Xiaoxin Qiu - Bridgewater NJ
Nelson R. Sollenberger - Tinton Falls NJ

Assignee:

ATT Corp - New York NY

International Classification:

H04Q 728

US Classification:

370341

Abstract:

An arrangement where, in addition to the control channels that are used to set up sessions, there is a logically and physically separate and independent set of control channels that can be used as session control channels. Illustratively, the physical GSM frame arrangement that employs 8 logical slots is used, with one slot both in the uplink and downlink dedicated to these separate control channels. In the downlink, such a control channel provides channel grant information, requests to make and transmit power measurements, poll mobile units, etc. In the uplink, such a control channel can be used to request access to a traffic channel, to report on power measurements, to request special hand-off handling, to respond to polling, etc. Because the uplink session control channel does not need to carry a significant amount of information, the GSM slot can be divided into minislots, with each minislot constituting a session control channel for a group of mobile units.

US Patent:

6681114, Jan 20, 2004

Filed:

Dec 6, 2000

Appl. No.:

09/731345

Inventors:

Li Fung Chang - Holmdel NJ
Hui Luo - Old Bridge NJ
Xiaoxin Qiu - Bridgewater NJ

Assignee:

ATT Corp. - New York NY

International Classification:

H04Q 720

US Classification:

4554563, 4554142, 37911413

Abstract:

An on-demand message system includes a profile proxy server and a plurality of message servers coupled to a wireless network for sending messages to mobile users under conditions specified by the users and sellers. Users provide profile information specifying categories and conditions for which they will receive messages. Sellers also provide profile information specifying conditions under which they want messages to be sent. A multicast message is sent and processed by target users in response to a predetermined event, e. g. , location update, conveying information related to a seller for which the target users have expressed an interest in receiving.

US Patent:

6754506, Jun 22, 2004

Filed:

Feb 16, 2001

Appl. No.:

09/784901

Inventors:

Li Fung Chang - Holmdel NJ
Kapil K. Chawla - Scotch Plains NJ
Justin Chi-I Chuang - Holmdel NJ
Zoran Kostic - Holmdel NJ
Xiaoxin Qiu - Bridgewater NJ
Nelson Ray Sollenberger - Farmingdale NJ
Shailender B. Timiri - Bellevue WA

Assignee:

ATT Wireless Services, Inc. - Redmond WA

International Classification:

H04Q 720

US Classification:

455522, 455 69, 4552451

Abstract:

A TDMA wireless communication system adjusts the power control target and transmission power based upon link quality to enhance voice capacity. The power can be adjusted in response to the average SNIR and number of decoding errors in a link quality reporting period. The power control target can be increased and decreased in discrete intervals after evaluating the number of decoding errors in the reporting period. The transmission power can be adjusted towards the new power control target based upon the average SNIR.

US Patent:

6950670, Sep 27, 2005

Filed:

Oct 31, 2001

Appl. No.:

10/001650

Inventors:

Li Fung Chang - Holmdel NJ, US
Kapil K. Chawla - Scotch Plains NJ, US
Justin Che-I Chuang - Holmdel NJ, US
Xiaoxin Qiu - Bridgewater NJ, US

Assignee:

AT&T Corp. - New York NY

International Classification:

H04Q007/20

US Classification:

455522, 455500, 455501, 455517, 455507, 455 6711, 455 6712, 455 6713, 455 6714, 455 6715, 375272, 379338

Abstract:

A wireless network includes transmission power and data rate adaptation based upon signal quality experienced by the user.

US Patent:

6954465, Oct 11, 2005

Filed:

Feb 22, 2001

Appl. No.:

09/791200

Inventors:

Li Fung Chang - Holmdel NJ, US
Kapil K. Chawla - Scotch Plains NJ, US
Justin Che-I Chuang - Holmdel NJ, US
Bruce Edwin McNair - Holmdel NJ, US
Xiaoxin Qiu - Bridgewater NJ, US

Assignee:

AT&T Corp. - New York NY

International Classification:

H04B007/212

US Classification:

370442, 370347

Abstract:

This invention provides interference predictions, suitable for least interference dynamic channel assignment use or other frequency hopping uses by de-coupling the time slot assignment and the frequency hopping pattern assignment. In particular, a least interfered time slot is selected based on an aggregate interference measurement performed across an entire transmission band or a pre-specified range of frequencies in the transmission band. A user is assigned a least interfered time slot and provided an appropriate frequency hopping pattern.

US Patent:

7027539, Apr 11, 2006

Filed:

Dec 9, 2003

Appl. No.:

10/731858

Inventors:

Baoguo Yang - Iselin NJ, US
Li Fung Chang - Holmdel NJ, US
Zhijun Gong - Iselin NJ, US

Assignee:

Broadcom Corporation - Irvine CA

International Classification:

H04B 1/10

US Classification:

375350, 375346, 455307, 708300

Abstract:

A wireless communication device processes N Radio Frequency (RF) bursts contained within N slots of a digital communications time divided frame, wherein N is a positive integer greater than one. The wireless communication device includes an RF front end, a baseband processor, and an equalizer module. The RF from end is operable to receive the plurality of received RF bursts and to convert the RF bursts to corresponding baseband signals. The baseband processor operably couples to the RF front end, is operable to receive the baseband signals, is operable to pre-equalization process the baseband signals to produce processed baseband signals, and is operable to post-equalization process soft decisions. The equalizer module operably couples to the baseband processor and is operable to equalize the processed baseband signals to produce the soft decisions. These RF bursts may be contained in adjacent slots or, in non-adjacent slots, or in a combination of adjacent slots and non-adjacent slots.

US Patent:

7035649, Apr 25, 2006

Filed:

Jan 8, 2004

Appl. No.:

10/753725

Inventors:

Li Fung Chang - Holmdel NJ, US
Hui Luo - Old Bridge NJ, US
Xiaoxin Qiu - Bridgewater NJ, US

Assignee:

AT&T Corp. - New York NY

International Classification:

H04Q 7/20

US Classification:

4554563, 4554142, 705 26

Abstract:

An on-demand message system includes a profile proxy server and a plurality of message servers coupled to a wireless network for sending messages to mobile users under conditions specified by the users and sellers. Users provide profile information specifying categories and conditions for which they will receive messages. Sellers also provide profile information specifying conditions under which they want messages to be sent. A multicast message is sent and processed by target users in response to a predetermined event, e. g. , location update, conveying information related to a seller for which the target users have expressed an interest in receiving.