4,612 research outputs found
On Complexity, Energy- and Implementation-Efficiency of Channel Decoders
Future wireless communication systems require efficient and flexible baseband
receivers. Meaningful efficiency metrics are key for design space exploration
to quantify the algorithmic and the implementation complexity of a receiver.
Most of the current established efficiency metrics are based on counting
operations, thus neglecting important issues like data and storage complexity.
In this paper we introduce suitable energy and area efficiency metrics which
resolve the afore-mentioned disadvantages. These are decoded information bit
per energy and throughput per area unit. Efficiency metrics are assessed by
various implementations of turbo decoders, LDPC decoders and convolutional
decoders. New exploration methodologies are presented, which permit an
appropriate benchmarking of implementation efficiency, communications
performance, and flexibility trade-offs. These exploration methodologies are
based on efficiency trajectories rather than a single snapshot metric as done
in state-of-the-art approaches.Comment: Submitted to IEEE Transactions on Communication
Comparison of Polar Decoders with Existing Low-Density Parity-Check and Turbo Decoders
Polar codes are a recently proposed family of provably capacity-achieving
error-correction codes that received a lot of attention. While their
theoretical properties render them interesting, their practicality compared to
other types of codes has not been thoroughly studied. Towards this end, in this
paper, we perform a comparison of polar decoders against LDPC and Turbo
decoders that are used in existing communications standards. More specifically,
we compare both the error-correction performance and the hardware efficiency of
the corresponding hardware implementations. This comparison enables us to
identify applications where polar codes are superior to existing
error-correction coding solutions as well as to determine the most promising
research direction in terms of the hardware implementation of polar decoders.Comment: Fixes small mistakes from the paper to appear in the proceedings of
IEEE WCNC 2017. Results were presented in the "Polar Coding in Wireless
Communications: Theory and Implementation" Worksho
XJ-BP: Express Journey Belief Propagation Decoding for Polar Codes
This paper presents a novel propagation (BP) based decoding algorithm for
polar codes. The proposed algorithm facilitates belief propagation by utilizing
the specific constituent codes that exist in the factor graph, which results in
an express journey (XJ) for belief information to propagate in each decoding
iteration. In addition, this XJ-BP decoder employs a novel round-trip message
passing scheduling method for the increased efficiency. The proposed method
simplifies min-sum (MS) BP decoder by 40.6%. Along with the round-trip
scheduling, the XJ-BP algorithm reduces the computational complexity of MS BP
decoding by 90.4%; this enables an energy-efficient hardware implementation of
BP decoding in practice.Comment: submitted to GLOBECOMM 201
Bandwidth efficient CCSDS coding standard proposals
The basic concatenated coding system for the space telemetry channel consists of a Reed-Solomon (RS) outer code, a symbol interleaver/deinterleaver, and a bandwidth efficient trellis inner code. A block diagram of this configuration is shown. The system may operate with or without the outer code and interleaver. In this recommendation, the outer code remains the (255,223) RS code over GF(2 exp 8) with an error correcting capability of t = 16 eight bit symbols. This code's excellent performance and the existence of fast, cost effective, decoders justify its continued use. The purpose of the interleaver/deinterleaver is to distribute burst errors out of the inner decoder over multiple codewords of the outer code. This utilizes the error correcting capability of the outer code more efficiently and reduces the probability of an RS decoder failure. Since the space telemetry channel is not considered bursty, the required interleaving depth is primarily a function of the inner decoding method. A diagram of an interleaver with depth 4 that is compatible with the (255,223) RS code is shown. Specific interleaver requirements are discussed after the inner code recommendations
Low-complexity blind maximum-likelihood detection for SIMO systems with general constellations
The demand for high data rate reliable communications poses great challenges to the next generation wireless systems in highly dynamic mobile environments. In this paper, we investigate the joint maximum-likelihood (ML) channel estimation and signal detection problem for single-input multiple-output (SIMO) wireless systems with general modulation constellations and propose an efficient sequential decoder for finding the exact joint ML solution. Unlike other known methods, the new decoder can even efficiently find the joint ML solution under high spectral efficiency non-constant- modulus modulation constellations. In particular, the new algorithm does not need such preprocessing steps as Cholesky or QR decomposition in the traditional sphere decoders for joint ML channel estimation and data detection. The elimination of such preprocessing not only reduces the number of floating point computations, but also will potentially lead to smaller size and power consumption in VLSI implementations while providing better numerical stability
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