Unequally protected multistage vector quantization for time-varying CDMA channels

Gadkari, S. C.; Rose, Kenneth

doi:10.1109/26.930634

Cited by 8 publications

(5 citation statements)

References 13 publications

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“…Many unequal protection techniques have been applied for the design of various robust modulation or coding systems. [7][8][9][10][11] In Refs. 9 and 10, the unequal protection is achieved by adopting the trellis-coded modulation with nonuniformly spaced constellation.…”

Section: Introductionmentioning

confidence: 99%

Robust layered image transmission based on genetic programming for noisy channels

Hwang

Lin

2001

Opt. Eng

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We present a novel robust layered image transmission (LIT) design algorithm for noisy channels. In the algorithm, the layered embedded zerotree wavelet (LEZW) coding technique is used to encode the images for the transmission of each layer. A new error protection allocation scheme based on genetic programming is then employed to determine the degree of protection for each layer so that the average distortion of the reconstructed images after transmission can be minimized. Simulation results show that, subject to the same amount of redundancy bits for error protection, the new algorithm outperforms other existing algorithms where equal-protection schemes are adopted.

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Section: Introductionmentioning

confidence: 99%

Robust layered image transmission based on genetic programming for noisy channels

Hwang

Lin

2001

Opt. Eng

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“…The trellis structure models the symbols and their assumed -order Markov property due to the residual redundancies. In this trellis structure, the states at time correspond to the ordered set (9) Hence, there are states in each time step (stage) . Each branch leaving the state at time step corresponds to one particular symbol .…”

Section: ) a Basic Solutionmentioning

confidence: 99%

“…The alternative solutions are provided based on different constructions of an extended trellis structure for the source coder output symbols. The states in this structure are referred to as the super states and are defined as (15) where is referred to as the (state set) extension factor and is the number of symbols by which the states (see (9)) have been extended to form the super states. Similar to the original trellis, there are branches leaving a (super) state in the extended trellis, where each branch corresponds to one symbol .…”

Section: ) a Basic Solutionmentioning

confidence: 99%

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Efficient Source Decoding Over Memoryless Noisy Channels Using Higher Order Markov Models

Lahouti

Khandani

2004

IEEE Trans. Inform. Theory

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Abstract-Exploiting the residual redundancy in a source coder output stream during the decoding process has been proven to be a bandwidth-efficient way to combat noisy channel degradations. This redundancy can be employed to either assist the channel decoder for improved performance or design better source decoders. In this work, a family of solutions for the asymptotically optimum minimum mean-squared error (MMSE) reconstruction of a source over memoryless noisy channels is presented when the redundancy in the source encoder output stream is exploited in the form of a -order Markov model ( 1) and a delay of 0 is allowed in the decoding process. It is demonstrated that the proposed solutions provide a wealth of tradeoffs between computational complexity and the memory requirements. A simplified MMSE decoder which is optimized to minimize the computational complexity is also presented. Considering the same problem setup, several other maximum a posteriori probability (MAP) symbol and sequence decoders are presented as well. Numerical results are presented which demonstrate the efficiency of the proposed algorithms.Index Terms-Forward-backward recursion, joint sourcechannel coding, maximum a posteriori probability (MAP) detection, Markov sources, minimum mean-squared error (MMSE) estimation, residual redundancies, source decoding.

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“…A variant of this decoder, is suggested for decoding of MSVQ encoded signals in [17]. The decoder MS1 is given in equation (6), and exploits both intraframe and interframe dependencies.…”

Section: Numerical Resultsmentioning

confidence: 99%

Reconstruction of multi-stage vector quantized sources over noisy channels - applications to MELP codec

Lahouti

Khandani

2004 IEEE International Conference on Acoustics, Speech, and Signal Processing

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Design of source decoders that employ the residual redundancy at the source coder output is an interesting research direction in the joint source channel coding framework. Such decoders are expected to replace the traditionally heuristic error concealment units that are elements of most multimedia communication systems. In this work, we consider the reconstruction of signals encoded with a Multi-Stage Vector Quantizer and transmitted over a noisy channel. The MSVQ maintains a moderate complexity and, due to its successive re£nement feature, is a suitable choice for the design of layered (progressive) source codes. An approximate MMSE source decoder for MSVQ is presented and its application to reconstruction of LPC parameters in MELP is analyzed. Numerical results demonstrates the effectiveness of the proposed schemes.

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Unequally protected multistage vector quantization for time-varying CDMA channels

Cited by 8 publications

References 13 publications

Robust layered image transmission based on genetic programming for noisy channels

Robust layered image transmission based on genetic programming for noisy channels

Efficient Source Decoding Over Memoryless Noisy Channels Using Higher Order Markov Models

Reconstruction of multi-stage vector quantized sources over noisy channels - applications to MELP codec

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