Patents by Inventor Rafi Rabipour
Rafi Rabipour has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7076316Abstract: A method and apparatus for controlling an operative setting of a communications link is provided. The communications link is capable of acquiring a plurality of operative settings. Audio quality in the communications link under different operative settings is compared and an operative setting is selected at least in part on the basis of this comparison. A control signal is sent to at least one component in the communications link to cause the communications link to attempt to acquire the selected setting.Type: GrantFiled: May 18, 2001Date of Patent: July 11, 2006Assignee: Nortel Networks LimitedInventors: Rafi Rabipour, Chung Cheung Chu, Paul Coverdale
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Patent number: 7006456Abstract: A conference bridge is provided for managing a conference between media signal sources generating media data packets conveying encoded media information and encoding type information. The media signal sources, in order to enter a conference, generate link messages including respective supported encoding types and transmit the link messages to the conference bridge. The conference bridge receives the link messages and processes them to derive a first common encoding type supported all media signal sources in the conference and a second encoding type supported a subset of media signal sources in the conference. The conference bridge generates link message reply signals conveying the first encoding type and the second encoding type the subset of media signal sources and conveying at least the first encoding type to the media signal sources other than the subset of all media signal sources.Type: GrantFiled: November 9, 2001Date of Patent: February 28, 2006Assignee: Nortel Networks LimitedInventors: Rafi Rabipour, Paul Coverdale, Paxton Smith
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Publication number: 20050114433Abstract: A conference bridge adapter for processing data carried on a media path between, on the one hand, a conference bridge operative to communicate composite packets carrying media information and auxiliary information pertaining to the media information and, on the other hand, an endpoint characterized by an inability to exchange composite packets with the conference bridge. In one direction, a stream of composite packets is received from the bridge. An output media stream without auxiliary information is generated from the media information in each received composite packet. In the opposite direction, a stream of packets carrying only media information is received from the endpoint. Auxiliary information is derived from the media information and a stream of composite packets is generated by combining the media information and the auxiliary information. Thus, a media conference can be established between seemingly incompatible network elements.Type: ApplicationFiled: November 26, 2003Publication date: May 26, 2005Inventors: Rafi Rabipour, Paul Coverdale
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Publication number: 20040252681Abstract: Communication apparatus having interfaces for exchanging data with first and second neighbors, a memory for storing codec information regarding the communication apparatus and a control entity operative to detect a message from the first neighbor, the first message being indicative of codec information regarding an originating entity. In response, the control entity assesses compatibility between the codec information regarding the originating entity and the codec information regarding the communication apparatus. If the assessment is positive, the control entity self-identifies the communication apparatus as a candidate for terminally supporting a subsequent codec-bypass negotiation with the originating entity. If the assessment is negative, the control entity self-identifies the communication apparatus as a candidate for non-terminally supporting such negotiation.Type: ApplicationFiled: February 23, 2004Publication date: December 16, 2004Inventors: Rafi Rabipour, Chung Cheung Chu
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Patent number: 6766291Abstract: The invention relates to a method and apparatus for controlling the transition of a bypass capable codec between operative modes, based on a certain characteristic of the audio data signal processed by the codec. The apparatus relies on a control signal to determine when the codec will switch from one mode to another. This control signal reflects a characteristic of the audio data signal received at the apparatus, such as the type of speech activity or the format of the audio data signal. When in the active (non-bypass) mode, the apparatus relies on an additional control signal to switch to the inactive (bypass) mode. This additional control signal is received from a control unit at a remote codec that indicates that the remote codec is also bypass capable, hence the decoder at the first codec and the encoder at the remote codec can switch to the inactive mode to pass between them the compressed data frames.Type: GrantFiled: June 18, 1999Date of Patent: July 20, 2004Assignee: Nortel Networks LimitedInventors: Chung Cheung C. Chu, Rafi Rabipour, David G. Sloan
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Publication number: 20040131051Abstract: A data communication apparatus, comprising an interface for enabling communication with a remote entity via a network and a control entity in communication with said interface. The control entity is operative to establish a packet-switched connection with the remote entity through the network and to negotiate with the remote entity using in-band signaling entry into a codec-bypass mode of operation. In this way, a codec-bypass connection, which enhances speech quality, can be established over a packet network, which reduces bandwidth.Type: ApplicationFiled: October 10, 2003Publication date: July 8, 2004Inventors: Rafi Rabipour, Chung Cheung Chu, Pierre Gendron, William Navarro, Paul Boudreaux
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Patent number: 6721707Abstract: A signal processor for effecting the conversion of an audio data signal from one format to another. The signal processor has a signal converter that can selectively acquire two operative modes, namely a first operative mode and a second operative mode. In the first operative mode, the signal converter transforms the audio data signal from one format to another and releases the converted audio data signal from the output of the signal processor. In the second operative mode, the signal converter is disabled and permits passage of the audio data signal to the output without conversion. The signal processor has a control unit for controlling the transition of the signal converter between operative modes. The control unit enables the signal converter to pass from the first operative mode to the second operative mode when at least one operating condition has been satisfied.Type: GrantFiled: December 22, 1999Date of Patent: April 13, 2004Assignee: Nortel Networks LimitedInventors: Chung Cheung C. Chu, Rafi Rabipour, David G. Sloan
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Publication number: 20040004957Abstract: Data communication apparatus including a port and a control entity. The control entity is operative to establish a connection with a remote entity over a first path and negotiate with the remote entity using in-band signaling over the first path establishment of a second path allowing the exchange of data between the data communication apparatus and the remote entity. The invention presents advantages from the standpoint of ease of implementation and bandwidth and resource savings. The use of an in-band messaging protocol to negotiate a establishment of the second path can be implemented generally in a straight forward manner. At the same time, the ability to transfer at least part of the connection to the second path avoids the drawbacks that would arise if that part of the connection were constrained to the first path. This feature allows the operator to take advantage of benefits provided by the second path but not available to the first path.Type: ApplicationFiled: September 6, 2002Publication date: January 8, 2004Inventors: Rafi Rabipour, Chung Cheung C. Chu, Pierre Gendron, William Navarro, Paul Boudreaux
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Publication number: 20030125960Abstract: The invention relates to a method and apparatus for controlling the transition of a bypass capable codec between operative modes, based on a certain characteristic of the audio data signal processed by the codec. The apparatus relies on a control signal to determine when the codec will switch from one mode to another. This control signal reflects a characteristic of the audio data signal received at the apparatus, such as the type of speech activity or the format of the audio data signal. When in the active (non-bypass) mode, the apparatus relies on an additional control signal to switch to the inactive (bypass) mode. This additional control signal is received from a control unit at a remote codec that indicates that the remote codec is also bypass capable, hence the decoder at the first codec and the encoder at the remote codec can switch to the inactive mode to pass between them the compressed data frames.Type: ApplicationFiled: June 18, 1999Publication date: July 3, 2003Inventors: CHUNG CHEUNG C. CHU, RAFI RABIPOUR, DAVID G. SLOAN
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Publication number: 20020107593Abstract: A method and apparatus for controlling an operative setting of a communications link is provided. The communications link is capable of acquiring a plurality of operative settings. Audio quality in the communications link under different operative settings is compared and an operative setting is selected at least in part on the basis of this comparison. A control signal is sent to at least one component in the communications link to cause the communications link to attempt to acquire the selected setting.Type: ApplicationFiled: May 18, 2001Publication date: August 8, 2002Inventors: Rafi Rabipour, Chung Cheung Chu, Paul Coverdale
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Publication number: 20020105917Abstract: A conference bridge is provided for managing a conference between media signal sources generating media data packets conveying encoded media information and encoding type information. The media signal sources, in order to enter a conference, generate link messages including respective supported encoding types and transmit the link messages to the conference bridge. The conference bridge receives the link messages and processes them to derive a first common encoding type supported all media signal sources in the conference and a second encoding type supported a subset of media signal sources in the conference. The conference bridge generates link message reply signals conveying the first encoding type and the second encoding type the subset of media signal sources and conveying at least the first encoding type to the media signal sources other than the subset of all media signal sources.Type: ApplicationFiled: November 9, 2001Publication date: August 8, 2002Inventors: Rafi Rabipour, Paul Coverdale, Paxton Smith
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Patent number: 6363339Abstract: In recent years, the telecommunications industry has witnessed the proliferation of a variety of digital vocoders in order to meet bandwidth demands of different wireline and wireless communication systems. The rapid growth in the diversity of networks and the number of users of such networks is increasing the number of instances where two vocoders are placed in tandem to serve a single connection. Such arrangements of low bit-rate codecs can degrade the quality of the transmitted speech. To overcome this problem in the specific situation involving store-and-forward systems (e.g. voicemail), the invention provides a novel method and apparatus including a plurality of different vocoders that can be selectively invoked to process the voice signal so as to reduce signal degradation. Also, the apparatus has the capability to bypass the vocoder bank when exchanging data with a remote signal processor capable of accepting data frames in compressed format.Type: GrantFiled: October 10, 1997Date of Patent: March 26, 2002Assignee: Nortel Networks LimitedInventors: Rafi Rabipour, Girish Patel
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Patent number: 6324515Abstract: This invention relates to a method and an apparatus for processing digital audio signals that may reduce the signal degradation occurring when the signal is exchanged between two communication terminals equipped with vocoders in a communication network. The solution proposed by this invention is to provide a communication terminal with a vocoder including a decoder section provided with a plurality of decoding units. A switch activates a selected one of the decoding units in dependence of the format of the compressed audio signal data frames received from a remote communication terminal. This system allows the communication terminal to support a number of different speech compression formals. In order to achieve simplicity and low cost, the communication terminal is provided with a single encoding unit. This results in an asymmetric arrangement where the communication terminal has a large number of decoding units than encoding units.Type: GrantFiled: June 2, 1998Date of Patent: November 27, 2001Assignee: Nortel Networks LimitedInventors: Rafi Rabipour, Paul Coverdale, William Navarro
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Patent number: 6185424Abstract: In a TDMA mobile-to-mobile connection, the end-to-end audio signal quality as well as system performance can be improved by providing digital signal processors the capability to automatically switch configuration such that each digital signal processor in a mobile-to-mobile communication connection can automatically identify a TDMA mobile-to-mobile connection and bypass the speech encoding and decoding processes within the digital signal processors. The two digital signal processors are virtually connected at the channel codecs.Type: GrantFiled: June 12, 1998Date of Patent: February 6, 2001Assignee: Nortel Networks LimitedInventors: Hermon Pon, Rafi Rabipour, Chung-Cheung Chu
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Patent number: 6148422Abstract: The present invention provides a system and a method for improving the voice quality of wireless-to-wireless calls. More specifically, the invention provides a method and an apparatus to add supplemental information for better error detection and correction of data packets. This feature allows the identification of the telecommunication link causing errors in the data packets and optimizes the use of the reconstructed data packets.Type: GrantFiled: October 7, 1997Date of Patent: November 14, 2000Assignee: Nortel Networks LimitedInventors: Leo Strawczynski, Bill Gage, Rafi Rabipour
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Patent number: 6138022Abstract: The present invention provides a novel system and a method for improving the voice quality of wireless-to-wireless calls or wireless-to-fixed terminal calls, while permitting a more efficient utilization of network resources. In a first aspect, the invention provides a communication system including a plurality of base stations connected to one another through a digital network (such as TDM, frame relay or ATM). Also, a plurality of vocoder channels, separate from the individual base stations, provide a data flow path from the base stations to wireline terminals first through the digital network via a Mobile Switching Center and finally through a landline network. In a wireless-to-wireless call, the compressed audio signal travels from one base station to another without undergoing any de-compression/compression. This avoids undesirable vocoder tandeming known to degrade voice quality.Type: GrantFiled: July 23, 1997Date of Patent: October 24, 2000Assignee: Nortel Networks CorporationInventors: Leo Strawczynski, Bill W. A. Gage, Rafi Rabipour
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Patent number: 6038452Abstract: The present invention provides novel systems and methods for improving the voice quality of wireless-to-wireless calls or wireless-to-fixed terminal calls. This disclosure describes methods and apparatuses to determine and control the quality of service objectives in a telecommunication network involving at least one wireless terminal.Type: GrantFiled: August 29, 1997Date of Patent: March 14, 2000Assignee: Nortel Networks CorporationInventors: Leo Strawczynski, Bill W. A. Gage, Rafi Rabipour
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Patent number: 6026356Abstract: The present invention relates to methods and devices for processing data frames representative of audio information in digitized and compressed form. The method comprises the steps of classifying successive data frames into frames containing speech sounds and non-speech sounds, altering parameters of the data frames identified as containing non-speech sounds for eliminating or at least substantially reducing artifacts that distort the acoustic background noise. In addition, the data frame identified as containing non-speech sounds are low-pass filtered. Finally, a signal level compensation is effected to avoid undesired fluctuations in the signal level.Type: GrantFiled: July 3, 1997Date of Patent: February 15, 2000Assignee: Nortel Networks CorporationInventors: H. S. P. Yue, Rafi Rabipour, Chung-Cheung Chu
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Patent number: 6011846Abstract: In methods and apparatus for suppressing echo of a far end signal encoded using LPC-based compression in a near end signal encoded using LPC-based compression, parameters of each frame of the near end encoded signal are processed without synthesizing a speech signal from the near end encoded signal to determine whether sufficient echo to merit echo suppression is present in the frame. Upon determining that insufficient echo to merit echo suppression is present in the frame, the parameters of the frame are passed unmodified. Upon determining that sufficient echo to merit echo suppression is present in said frame, the parameters of the frame are modified without synthesizing a speech signal to suppress echo in the frame. The methods and apparatus are particularly suitable in codec bypass applications.Type: GrantFiled: June 24, 1997Date of Patent: January 4, 2000Assignee: Nortel Networks CorporationInventors: Rafi Rabipour, Dominic Ho, Majid Foodeei, Madeleine Saikaly
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Patent number: 5995923Abstract: In recent years, the telecommunications industry has witnessed the proliferation of a variety of digital vocoders in order to meet bandwidth demands of different wireline and wireless communication systems. The rapid growth in the diversity of networks and the number of users of such networks is increasing the number of instances where two vocoders are placed in tandem to serve a single connection. Such arrangements of low bit-rate codecs can degrade the quality of the transmitted speech. To overcome this problem the invention provides a novel method and an apparatus for transmitting digitized voice signals in the wireless communications environment. The apparatus is capable of converting a compressed speech signal from one format to another format via an intermediate common format, thus avoiding the necessity to successively de-compress voice data to a PCM type digitization and then recompress the voice data.Type: GrantFiled: June 26, 1997Date of Patent: November 30, 1999Assignee: Nortel Networks CorporationInventors: Paul Mermelstein, Rafi Rabipour, William Navarro, Paul Coverdale