Yichyun M Tseng

6556824, Apr 29, 2003

Oct 28, 1999

09/429759

Rene W. Purnadi - Coppell TX
Liangchi Hsu - Arlington TX
Yichyun Tseng - Plano TX

Nokia Corporation - Espoo

H04Q 720

455422, 455432, 455434

Apparatus, and an associated method, facilitates service degradation in a radio communication system, such as a cellular communication system. A service degradation profile is created, associated with a particular communication service-type, and includes values of QoS (quality of service) level values. If communication at levels corresponding to the values of the desired QoS level parameters is unavailable, efforts are made to effectuate, or maintain communication at quality levels corresponding to values of at least first QoS level parameters values. Service degradation thereby occurs pursuant to a selected profile, reducing the need for service renegotiations and reducing the possibility that an abrupt termination of a communication session might occur.

7349695, Mar 25, 2008

Oct 14, 2004

10/963629

Paul Oommen - Irving TX, US
Yichyun Mitch Tseng - Plano TX, US

Nokia Corporation - Espoo

H04Q 7/20
H04Q 7/32

4554321, 4554322, 4554352, 4554351, 4554323, 4555501, 455551, 4554221

A mobile device for roaming between wireless communications networks in different geographical regions is provided. The mobile device includes an interface configured to transmit and receive signals over a wireless channel according to a communication mode using one of a plurality of access technologies. The device also includes a store holding a preferred roaming list having a common block holding data common to the plurality of access technologies, and a set of access technology-specific blocks each holding channel acquisition data specific to one of the plurality of access technologies for setting up the communication mode.

61729744, Jan 9, 2001

Oct 31, 1997

8/961953

Yichyun Tseng - Plano TX
Amarjit Deol - Plano TX

Nortel Networks Limited - Montreal

H04Q 1100

370357

A method and apparatus for achieving tandem free operation (TFO) including bypass transcoding and cross transcoding in a communication system. The present invention provides communication of compressed voice signals, or voice signals compressed in a common format, between wireless mobile stations across a PSTN by bypassing vocoders residing in the MSC/BSC of the communication system, or between network elements of an ATM network. In a wireless network, a capability signal, preferably being a low frequency tone, is transmitted by the terminating MSC/BSC to the originating MSC/BSC to indicate that the terminating element is capable of transcoding or transcoding and cross transcoding. The originating element responsively generates an optional LF tone and a 2100 Hz tone to disable network cancellers between the originating element and the terminating element in the forward direction. The terminating element, then, responsively generates a 2100 Hz tone to disable network echo cancellers between the terminating element and the originating element in the backward direction, whereby the vocoders of the network are bypassed. Compression and decompression of voice signals is only provided by the vocoders integrated into the terminating wireless mobile stations.