System and method for dynamically changing error algorithm redundancy levels

• US 7,286,562 B1
• Filed: 11/06/2001
• Issued: 10/23/2007
• Est. Priority Date: 08/08/1997
• Status: Expired due to Fees

• Current Assignee: Advent IP LLC
• Original Assignee: Verso Technologies Incorporated
• Inventors: Vargo, Mike, Chang, Jerry
• Primary Examiner(s): To, Doris H.
• Assistant Examiner(s): Rose, Kerri M
• Application Number:
  US09/993,104
• Time in Patent Office: 2,177 Days
• Field of Search: 370352-356, 370/401, 370/465
• US Class Current: 370/468
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: H03M 13/03 Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H04L 1/0006 by adapting the transmission format
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0014 by adapting the source coding
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04M 3/12 Marking faulty circuits "busy"; Enabling equipment to disengage itself from faulty circuits ; Using redundant circuits; Response of a circuit, apparatus or system to an error
• CPC Class Codes: H04M 7/1275 Methods and means to improve the telephone service quality, e.g. reservation, prioritisation or admission control

Abstract

The invention is concerned with improvements in full duplex Internet telephone systems with a system architecture having low latency and permitting voice communication with telephone to telephone or PC to telephone connections. The architecture permits dynamic packet-to-packet change in codec to adjust for Internet conditions. The voice port creates self-describing packet conditions so that the higher-level software of the system is independent of codec selection. In addition to adjusting the codec, the voice port has the capability of dynamically and concurrently selecting other factors such as the level of error correction redundancy, the packet size and packet bundling on a packet-to-packet basis. The invention further includes a technique to eliminate dead air spaces in the voice data transmission stream by speeding up or slowing down the data rate in the buffer while maintaining a constant pitch of speech.

Claims

1. A system architecture for an internet telephone gateway server, comprising:

hardware for interfacing with the internet and a public switched telephone network; and

software for connecting telephone calls between transmitters and receivers, said software having the capability of dynamically changing a level of redundancy of a forward error correction algorithm from packet-to-packet in a data stream so as to accommodate data dropouts,

whereby aural data in a packet is entirely duplicated to maintain the voice quality present prior to the data dropout.

2. The system architecture of claim 1, wherein said gateway server supports full duplex voice transmission with a latency of less than 500 milliseconds.

3. The system architecture of claim 1, wherein said software has the capability of dynamically varying the size or bundling of a data packet from packet-to-packet.

4. The system architecture of claim 1, wherein said software has the capability of dynamically varying from one codec to another codec from packet-to-packet.

5. The system architecture of claim 1, wherein said software varies the size or bundling of data packets from packet-to-packet.