Nortel Networks Corporation

Texas Instruments Corporation

Slobodan Jovanovic

Kim Bryon Roberts

Chandra Sekhar Bontu

Han Henry Sun

Kuang Tsan Wu

Aleksandar Purkovic

Mehul Mehta

Jianzhong Xu

Brian Francis Johnson

Steven Alan Tretter

Zongyao Zhou

A decoding circuit, is provided, comprising: a turbo decoder configured to receive a input systematic bit soft information values and input parity bit information values, and to generate output systematic bit soft information values and hard decoded bits according to a turbo decoding operation; and a parity bit soft information generation circuit configured to receive the input systematic bit soft information values, the input parity bit soft information values, and the output systematic bit soft information values; to determine initial forward metrics, initial backward metrics, and branch metrics as a function of the input parity bit soft information values and the output systematic bit soft information values; to determine output parity bit soft information values based on the branch metrics, the initial forward metrics, and the initial backward metrics; and to provide the output parity bit soft information values as a signal output.

System and method for determining parity bit soft information at a turbo decoder output

A method of recovering a clock signal from an optical signal received through an optical communications system. A digital sample stream is processed to generate a dispersion compensated signal. The dispersion compensated signal is then tapped to obtain upper side band and lower side band signals of each received polarization of the optical signal. The upper side band and lower side band signals are then processed to compensate polarization dependent impairments, and the clock recovered from the resulting optimized.

Clock recovery from an optical signal with dispersion impairments

A method of recovering a clock signal from an optical signal received through an optical communications system. A digital sample stream is processed to generate a dispersion compensated signal. The dispersion compensated signal is then tapped to obtain upper side band and lower side band signals of each received polarization of the optical signal. The upper side band sand lower side band signals are then processed to compensate polarization dependent impairments and the clock recovered from the resulting optimized.

Clock recovery from an optical signal with polarization impairments

A method and apparatus for exchanging data rate information across a packet-based network, is presented herein. In accordance with an embodiment of the invention, a first and second communication device, configured to operate as data sources, sinks, or both, communicate with a first and second gateway mechanism, respectively. The first gateway mechanism receives data rate information from the first communication device to determine a first data signaling rate between the first communication device and the first gateway mechanism. Similarly, the second gateway mechanism receives data rate information from the second communication device to determine a second data signaling rate between the second communication device and the second gateway mechanism. The first gateway forwards data rate information containing the first data signaling rate to the second gateway mechanism and the second gateway mechanism forwards data rate information containing the second data signaling rate to the first gateway mechanism. The first communication device and the first gateway mechanism determine a maximum compatible source-to-sink data rate based on the first data signaling rate and the second data signaling rate received from the second gateway mechanism and the second communication device and the second gateway mechanism determine a maximum compatible source-to-sink data rate based on the second data signaling rate and the first data signaling rate received from the first gateway mechanism.

Method of data rate exchange for transmissions across a packet-based network

A method and apparatus for establishing communication between a sending facsimile machine and a receiving facsimile machine first receives an answer tone message for a specified time. It then is determined if a given joint menu message has been received from the receiving facsimile machine at any time during the specified time. If it is determined that the given joint menu message has not been received from the receiving facsimile machine at any time during the specified time, then the above noted alias joint menu message is forwarded to the sending facsimile machine. The alias joint menu message is different from the given joint menu signal and thus, not a true joint menu message that can be used by the sending facsimile machine.

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Bethesda, MD, United States of America

Slobodan Jovanovic