Transmission Errors and Forward Error Correction in Embedded Differential Pulse Code Modulation

Goodman, D.J.; Sundberg, C.-E.W.

doi:10.1002/j.1538-7305.1983.tb03202.x

Cited by 22 publications

(1 citation statement)

References 12 publications

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“…expressing P w in terms of the average bit error probability P, we haveN = L PW(1 -P)N-wS w. w=1 (20)From eqs (16). to(19) we observe that Sw is the sum of the A-factors associated with the Qw error sequencies let!…”

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Transmission Errors in Companded PCM Over Gaussian and Rayleigh Fading Channels

Steele

Sundberg

Wong

1984

At&T Bell Laboratories Technical Journal

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Transmission errors in μ‐law pulse‐code‐modulated systems are capable of inflicting considerable distortion in the recovered analog signals. We analyze this distortion when the transmission is over radio channels, and when either noncoherent frequency shift keying or coherent phase shift keying (CPSK) modulation is employed. We consider both Gaussian and Rayleigh fading channels, and for the latter we investigate the effect of bit scrambling prior to transmission and two types of diversity. We determined the gain in overall signal‐to‐noise ratio due to using the minimum distance code compared to the conventional folded binary code for low values of input signal power. In addition to the theoretical results, we present computer simulations of μ‐law pulse‐code‐modulated encoded speech transmitted over the same channels, using CPSK modulation, bit scrambling, and diversity where appropriate, i.e., for the same conditions as employed in the derivation of our theory.

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Transmission Errors in Companded PCM Over Gaussian and Rayleigh Fading Channels

Steele

Sundberg

Wong

1984

At&T Bell Laboratories Technical Journal

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WirelessIPTelephony

Famolari¹

2003

Wiley Encyclopedia of Telecommunications

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Both the Internet and wireless telephony have created unprecedented operating freedoms that are forcing paradigm shifts in business and social communication practices. Their impact, however, has emerged from opposite design philosophies. The wireless telephone network was designed to provide mobile access to speech applications; the Internet, on the other hand, was designed to deliver a wide variety of application types to fixed locations. The freedom and mobility offered by wireless networks provides a perfect compliment to the economies of scale and flexibility offered by the IP‐based Internet. As IP becomes an important driver of both core and access networks, it must support wireless voice at comparable levels of spectrum efficiency and voice quality as cellular telephony. Similarly, wireless network practices must be modified to accommodate IP‐based packet protocols. It is our aim here to describe the design challenges and technical hurdles facing successful deployment of wireless IP telephony.

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Combined Source and Channel Coding for Variable-Bit-Rate Speech Transmission

Goodman¹,

Sundberg²

1983

Bell System Technical Journal

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Motivated by potential applications to mobile radio, we studied variablebit-rate speech communication through Gaussian-noise and Rayleigh-fading channels. For convenience we used a constant signaling rate of 32 kb/s and adjusted the source-coding and channel-coding rates in response to changing transmission quality. When the channel quality was good enough, we used all 32 kb/s for speech transmission. When the channel quality was lower, we reduced the source rate to 24 or 16 kb/s and introduced channel coding to control distortion due to transmission errors. We concentrated on specific source and channel codes that could be implemented with hardware of modest complexity. The source code was embedded differential pulse code modulation, which is amenable to variable-bit-rate operation and economical to implement. For error control we introduced punctured convolutional codes and a Viterbi decoder with only 16 states. Although the source/channel codec was simple, it offered good performance. Speech quality was at the level of normal telephony when the channel was good; the error-correcting codes extended by up to 13 dB the range of channel signal-to-noise ratios that support adequate quality. Our performance estimates were based on a new analysis of transmission errors in embedded differential pulse code modulation and on computer simulations of speech transmission through fixed and fading channels.

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Transmission Errors and Forward Error Correction in Embedded Differential Pulse Code Modulation

Cited by 22 publications

References 12 publications

Transmission Errors in Companded PCM Over Gaussian and Rayleigh Fading Channels

Transmission Errors in Companded PCM Over Gaussian and Rayleigh Fading Channels

WirelessIPTelephony

Combined Source and Channel Coding for Variable-Bit-Rate Speech Transmission

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