Method and system for encoding to mitigate decoding errors in a receiver

Abstract

In a data transmitter having a data encoder, an encoder mode is detected. Thereafter, an excluded codeword output by the encoder operating in the encoder mode is identified. Next, a selected bit in the excluded codeword caused to have a predetermined value to produce a non-excluded codeword. Finally, the excluded codeword is substituted with the non-excluded codeword, wherein the non-excluded codeword is selected to mitigate effects of a decoding error in a receiver associated with the excluded codeword.

Description

[0001] This application claims priority to US Application Serial No. 60 / 186,819, filed March 3,2000. technical field [0002] The present invention relates generally to digital communication systems, and more particularly to a method and system for encoding data to avoid or reduce decoding errors in a receiver. Background technique [0003] In some digital communication systems, digital samples of speech are input to a speech coder or vocoder to generate encoded speech packets for transmission to remote receivers, such as subscriber units in the wireless communication system. In a typical system, a voice encoder or codec might generate a voice packet every 20 milliseconds. [0004] For various reasons such as increasing system capacity, the speech packets output by the vocoder may comprise different numbers of bits, depending on the mode of operation of the vocoder, which may be determined by the speech activity. Speech activity is a method of quantifying the amount of spee...

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Problems solved by technology

Audio artifacts can also be caused by dropped frames, undetected bit errors, encoding or decoding quantization errors, filter overflow errors, etc.

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