3,151 research outputs found
A New Class of Multiple-rate Codes Based on Block Markov Superposition Transmission
Hadamard transform~(HT) as over the binary field provides a natural way to
implement multiple-rate codes~(referred to as {\em HT-coset codes}), where the
code length is fixed but the code dimension can be varied from
to by adjusting the set of frozen bits. The HT-coset codes, including
Reed-Muller~(RM) codes and polar codes as typical examples, can share a pair of
encoder and decoder with implementation complexity of order .
However, to guarantee that all codes with designated rates perform well,
HT-coset coding usually requires a sufficiently large code length, which in
turn causes difficulties in the determination of which bits are better for
being frozen. In this paper, we propose to transmit short HT-coset codes in the
so-called block Markov superposition transmission~(BMST) manner. At the
transmitter, signals are spatially coupled via superposition, resulting in long
codes. At the receiver, these coupled signals are recovered by a sliding-window
iterative soft successive cancellation decoding algorithm. Most importantly,
the performance around or below the bit-error-rate~(BER) of can be
predicted by a simple genie-aided lower bound. Both these bounds and simulation
results show that the BMST of short HT-coset codes performs well~(within one dB
away from the corresponding Shannon limits) in a wide range of code rates
A High-Throughput Energy-Efficient Implementation of Successive-Cancellation Decoder for Polar Codes Using Combinational Logic
This paper proposes a high-throughput energy-efficient Successive
Cancellation (SC) decoder architecture for polar codes based on combinational
logic. The proposed combinational architecture operates at relatively low clock
frequencies compared to sequential circuits, but takes advantage of the high
degree of parallelism inherent in such architectures to provide a favorable
tradeoff between throughput and energy efficiency at short to medium block
lengths. At longer block lengths, the paper proposes a hybrid-logic SC decoder
that combines the advantageous aspects of the combinational decoder with the
low-complexity nature of sequential-logic decoders. Performance characteristics
on ASIC and FPGA are presented with a detailed power consumption analysis for
combinational decoders. Finally, the paper presents an analysis of the
complexity and delay of combinational decoders, and of the throughput gains
obtained by hybrid-logic decoders with respect to purely synchronous
architectures.Comment: 12 pages, 10 figures, 8 table
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