In this paper we propose a scheme for rate adaptive lossless distributed source coding scheme for wireless sensor network. We investigate the distributed source-channel coding of correlated sources when correlation pa...
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ISBN:
(纸本)9783642205729
In this paper we propose a scheme for rate adaptive lossless distributed source coding scheme for wireless sensor network. We investigate the distributed source-channel coding of correlated sources when correlation parameter is not fixed or may change during sensor network operation. For achieving rate adaptability we propose the puncturing and extension of ira code depending on the value of correlation between two sources and the quality of channel. In our scheme we need to transmit only incremental redundancy for decreased correlation or fall in channel quality to meet energy constraints and reducing computation cost.
While LDPC codes have been widely acclaimed in recent years for their near-capacity performance, they have not found their way into many important applications. For some cases, this is due to their increased decoding ...
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While LDPC codes have been widely acclaimed in recent years for their near-capacity performance, they have not found their way into many important applications. For some cases, this is due to their increased decoding complexity relative to the classical coding techniques. For other cases, this is due to their inability to reach very low bit error rates (e.g., 10(-12)) at low signal-to-noise ratios (SNRs), a consequence of the error-rate floor phenomenon associated with iterative LDPC decoders. In the present paper, we make strides in the low-floor problem by identifying the weaknesses of the code under study and applying compensatory counter-measures. These counter-measures include: modifying the code itself, modifying the decoder, or adding a properly designed outer algebraic code. Our results demonstrate that each of these techniques can successfully lower an LDPC code's floor, and that, for the code under study, an outer BCH code appears to be particularly effective. All of our results are based on FPGA decoder simulations and so they are reliable and repeatable.
An incremental redundancy hybrid automatic repeat- request （IR-HARQ）scheme based on irregular repeat-accumulate （ira）codes is proposed. The design of rate compatible punctured ira codes suitable for an IR-HARQ sch...
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An incremental redundancy hybrid automatic repeat- request （IR-HARQ）scheme based on irregular repeat-accumulate （ira）codes is proposed. The design of rate compatible punctured ira codes suitable for an IR-HARQ scheme is well formulated and efficiently solved by a linear-programming method, along with a one-dimensional approach for density evolution. Compared to IR-HARQ schemes based on turbo codes, simulation shows that the proposed IR-HARQ schemes based on ira codes may achieve almost the same performance at a block size of 1 024, but better throughput at a block size of 4 096. The advantages of the proposed scheme in implementation, including decoding complexity and parallelism, make it more attractive in practice than the IR-HARQ schemes based on both turbo and LDPC codes.
Low-density mirror-concatenated (LDMC) codes are defined and shown to be equivalent to low-density parity-check (LDPC) codes. As a generalization of irregular repeat-and-accumulate (ira) codes, LDMC codes offer a slig...
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ISBN:
(纸本)0780382803
Low-density mirror-concatenated (LDMC) codes are defined and shown to be equivalent to low-density parity-check (LDPC) codes. As a generalization of irregular repeat-and-accumulate (ira) codes, LDMC codes offer a slightly different, but potentially useful, perspective on LDPC codes as concatenated codes.
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