Channel Codes That Exploit the Residual Redundancy in CELP- Encoded Speech

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dc.contributor.authorAlajaji, Fadyen_US
dc.contributor.authorPhamdo, N.en_US
dc.contributor.authorFuja, Tom E.en_US
dc.contributor.departmentISRen_US
dc.date.accessioned2007-05-23T09:59:08Z
dc.date.available2007-05-23T09:59:08Z
dc.date.issued1995en_US
dc.description.abstractWe consider the problem of reliably transmitting CELP-encoded speech over noisy communication channels. Our objective is to design efficient coding/decoding schemes for the transmission of the CELP line spectral parameters (LSP's) over very noisy channels.<P>We begin by quantifying the amount of ﲲesidual redundancy inherent in the LSP's of Federal Standard 1016 CELP. This is done by modeling the LSP's as first-and second-order Markov chains. Two models for LSP generation are proposed; the first model characterizes the intra-frame correlation exhibited by the LSP's, while the second model captures both intra-frame and inter-frame correlation. By comparing the entropy rates of the models thus constructed with the CELP rates, it is shown that as many as one-third of the LSP bits in every frame of speech are redundant.<P>We next consider methods by which this residual redundancy can be exploited by an appropriately designed channel decoder. Before transmission, the LSP's are encoded with a forward error control (FEC) code; we consider both (Reed-Solomon) codes and convolutional codes. Soft-decision decoders that exploit the residual redundancy in the LSP's are implemented assuming additive white Gaussian noise (AWGN) and independent Rayleigh fading environments. Simulation results employing binary phase-shifting keying (BPSK) indicate coding gains of 2 to 5 dB over soft-decision decoders that do not exploit the residual redundancy.en_US
dc.format.extent1149808 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/1903/5638
dc.language.isoen_USen_US
dc.relation.ispartofseriesISR; TR 1995-50en_US
dc.subjectdigital communicationsen_US
dc.subjecterror-detection codesen_US
dc.subjectinformation theoryen_US
dc.subjectspeech processingen_US
dc.subjectCELPen_US
dc.subjectchannel codingen_US
dc.subjectvery noisy AWGN channelsen_US
dc.subjectRayleigh fading channelsen_US
dc.subjectIntelligent Signal Processing en_US
dc.subjectCommunications Systemsen_US
dc.titleChannel Codes That Exploit the Residual Redundancy in CELP- Encoded Speechen_US
dc.typeTechnical Reporten_US

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