Contention-free interleavers

Nimbalker, Ajit; Fuja, T.E.; Costello, Daniel J.; Blankenship, T.K.; Classon, B.

doi:10.1109/isit.2004.1365089

Cited by 26 publications

(24 citation statements)

References 1 publication

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“…Designing the interleaving pattern wisely can prevent such collision [1] and empirical results show that these contention-free interleavers can yield similar performance as conventional interleavers designed for serial implementation [2,3] . However, we notice that they are all constructed in a semi-random way so that at least one part of the interleaver pattern must be stored explicitly, which can be inconvenient when support for different code length is required.…”

Section: Introductionmentioning

confidence: 97%

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A reordered first fit algorithm based novel storage scheme for parallel turbo decoder

Zhang

et al. 2007

J. of Shanghai Univ.

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In this paper we discuss a novel storage scheme for simultaneous memory access in parallel turbo decoder. The new scheme employs vertex coloring in graph theory. Compared to a similar method that also uses unnatural order in storage, our scheme requires 25 more memory blocks but allows a simpler configuration for variable sizes of code lengths that can be implemented on-chip. Experiment shows that for a moderate to high decoding throughput (40∼100 Mbps), the hardware cost is still affordable for 3GPP's (3rd generation partnership project) interleaver.

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Section: Introductionmentioning

confidence: 97%

“…A decoder using parallel maximum a priori (MAP) algorithm contains multiple soft-inputsoft-output (SISO) modules [1] , so parallel access to these storages is required. When translated into hardware design, it means that data required by different SISOs at the same time must not be stored in the same RAM block.…”

Section: Introductionmentioning

confidence: 99%

A reordered first fit algorithm based novel storage scheme for parallel turbo decoder

Zhang

et al. 2007

J. of Shanghai Univ.

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“…3GPP LTE requires high degree of parallelism [15,26], which can be achieved by overcoming memory access contention problem. [27][28][29][30] present the first approaches to solve the memory access contention problem by designing the contentionfree interleavers. Quadratic permutation polynomial (QPP) interleaver [9] has been proposed as a contention-free, parallel interleaver suitable for 3GPP-LTE.…”

Section: Introductionmentioning

confidence: 99%

Novel Interleaver Design for Turbo Codes

Pasricha

Sharma

2015

Wireless Pers Commun

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Interleaving is frequently used in digital communication and storage systems to improve the performance of forward error correcting codes. For turbo codes, an interleaver is an integral component and its proper design is crucial for good performance. Quadratic permutation polynomial (QPP) interleaver is a contention-free interleaver which is suitable for parallel turbo decoder implementation. This paper proposes a novel interleaver design, a variant of QPP interleaver, for turbo codes, which permutes a sequence of bits with the same statistical distribution as a conventional QPP interleaver and performs as well as or better than the conventional QPP. Proposed architecture has been simulated and synthesized using Xilinx and HDL Designer tools. Very large scale integration architecture for the proposed interleaver has been presented and analyzed for trade-off in terms of area, delay and power dissipation. Thermal power dissipation and device utilization have been computed for the proposed design using QuartusII (32-bit) tool. The paper also presents a comparison between the proposed variant of QPP interleaver and the conventional QPP interleaver.

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“…The first approaches to solve the memory access contention problem simply avoided it by constraining the interleavers to be contention-free as in [2], [3], [5], [16]. For these type of constrained constructions of interleavers, Nimbalker et al have shown that only a very small fraction of all interleavers are suitable for parallel processing of iterative decoding [2]. They have also proposed a new construction of a modified dithered relatively prime 3 interleaver [8] (DRP) interleaver.…”

Section: Introductionmentioning

confidence: 99%

“…1 In turbo coding applications, this property is also desirable in the reverse order, i.e., when subblock 0 and 1 switch roles. A mathematical description of the contention-free condition from [2] is now given. The exchange and processing of a sequence of N = MW extrinsic information symbols between sub-blocks of the iterative decoder can be parallelized by M processors working on window sizes of length W in each sub-block without contending for memory access provided that the following condition holds for both the interleaver f (x), 0 ≤ x < N and deinterleaver where 0 ≤ j < W , 0 ≤ t < v < N/W , and π(·) is either f (·) or g(·).…”

Section: Introductionmentioning

confidence: 99%

On maximum contention-free interleavers and permutation polynomials over integer rings

Takeshita

2006

IEEE Trans. Inform. Theory

142

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An interleaver is a critical component for the channel coding performance of turbo codes. Algebraic constructions are of particular interest because they admit analytical designs and simple, practical hardware implementation. Contention-free interleavers have been recently shown to be suitable for parallel decoding of turbo codes. In this correspondence, it is shown that permutation polynomials generate maximum contention-free interleavers, i.e., every factor of the interleaver length becomes a possible degree of parallel processing of the decoder. Further, it is shown by computer simulations that turbo codes using these interleavers perform very well for the 3rd Generation Partnership Project (3GPP) standard.

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Contention-free interleavers

Cited by 26 publications

References 1 publication

A reordered first fit algorithm based novel storage scheme for parallel turbo decoder

A reordered first fit algorithm based novel storage scheme for parallel turbo decoder

Novel Interleaver Design for Turbo Codes

On maximum contention-free interleavers and permutation polynomials over integer rings

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