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Many wireless sensor networks require the acquisition and transmission of high-precision analog sensor outputs. To force analog data into digital transmission systems inevitably causes irrecoverable quantization errors, (significant) bandwidth expansion, and the “significant-vs-insignificant bit” problem. This paper proposes a new transmission paradigm that exploits a single analog error correction...
A new class of analog codes based on 2-dimensional discrete-time chaotic systems, the baker's map, are proposed. The fundamental idea is to effectively transform the "sensitivity-to-initial-condition" property of a chaotic system to serve the "distance expansion" condition required by a good error correction code. By cleverly applying the baker's map on the tent map to achieve...
This paper proposes a novel construction of analog codes based on nonlinear chaotic dynamical systems in general and the tent map in particular. In light of the importance of the symbolic coding in estimating tent chaos, the proposed construction exploit useful ideas of interleaving and parallel concatenation from classical coding theory to protect symbolic coding and subsequently chaotic states....
Utilization of redundancy left in a channel coded sequence can improve channel decoding performance. Stronger improvement can usually be achieved with nonsystematic encoding. However, nonsystematic codes recently proposed for this problem are not robust to the statistical parameters governing a sequence and thus should not be used without prior knowledge of these parameters. In this work, decoders...
Accumulate-turbo codes are proposed for use in channel coding of data that contains redundancy. Accumulate-turbo codes are nonsystematic channel codes that consist of a cascade of an outer accumulator, an interleaver, and an inner turbo code. The outer accumulator acts as a rate one source code, which allows better utilization of redundancy already in the data in channel decoding than in other previously...
Non-systematic channel encoding can be superior to systematic encoding in the presence of redundancy in the transmitted data. The advantage becomes more significant the higher the channel coding rate is. However, known turbo like codes for this purpose only perform well at low channel coding rates. Furthermore, typical non-systematic codes designed for this problem usually suffer from lack of robustness...
We investigate good coprime interleavers that perform well in turbo codes and allow for memory-efficient implementation. We first evaluate the spread and the randomness properties of these interleavers using the cycle correlation sum (CCS) and the variance of the second order spread spectrum (VSSS) criteria, respectively. A critical parameter cpower is introduced for interleavers whose lengths are...
This paper investigates the adaptive ARQ method for turbo coded communication systems in the fast deep fading environment. Different from the traditional ARQ method, this approach provides various throughput for different quality of service (QoS) in the transportation communications. Based on the typical phenomena observed in the turbo coded communication systems under fast deep fading channels, we...
Differential unitary space-time modulation (DUSTM) is well established for high data rate communications in the multi-antennas channel without channel state information (CSI). To achieve the channel capacity, a new scheme, which employs the turbo-trellis coded modulation (TTCM) and DUSTM, is proposed in this paper. Simulation results reveal that in the TTCM-DUSTM scheme, around 12 dB coding gain is...
Non-systematic channel codes can have a significant advantage over systematic codes when utilizing redundancy left in the data for channel decoding. However, results previously attained show that even with such codes there is a performance gap to the theoretical limits. We propose a method that combines unequal energy allocation with source controlled decoding of non-systematic turbo codes. The method...
We consider strategies for universal utilization of context based redundancy left in channel coded data to improve channel decoding of non-systematic turbo codes. The statistical parameters of the sequence are extracted using such strategies and passed to an iterative decoder. Simulation results demonstrate significant coding gains obtained by utilization of this redundancy, which usually increase...
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