1,721,002 research outputs found
Existence and uniqueness of the solution for turbo decoding of parallel concatenated Single Parity Check codes
No full textMarch 200
Rate variable, multi-binary turbo codes with controlled error-floor
No full textIn this letter we propose rate variable turbo codes
based on the parallel concatenation of tailbiting Recursive
Systematic multi-binary (m-ary) convolutional codes. Rate variability
is not achieved by puncturing, which can have adverse
effects on the minimum distance of the code. Using a variable
number of input lines of the encoder, we obtain several different
overall rates ranging from 1/2 to 7/8. The most suitable Soft-In-
Soft-Out decoding algorithm for these turbo codes is based on
the Dual Reciprocal Code, which is very efficient for high rate
codes.
A particular interleaver design, namely the “backbone” interleaver,
guarantees a high Hamming weight in codewords with
information weight 2 and 3, as well as good minimum distances
and fairly low multiplicities for higher information weights.
Therefore, these codes have very low error floors
On the Throughput of an ALOHA Channel with Variable Length Packets
No full textIn this paper we give a new simple expression for the probability of successful transmission on an infinite population ALOHA channel with variable length packets. Expressions for the throughput and the probability density of the packet length on the channel are derived in a straightforward way along with the best and the worst length densities
On the Throughput of an ALOHA Channel with Variable Length Packets
No full textIn this paper we give a new simple expression for the probability of successful transmission on an infinite population ALOHA channel with variable length packets. Expressions for the throughput and the probability density of the packet length on the channel are derived in a straightforward way along with the best and the worst length densities
Refinements and Asymptotic performance of Bandwidth-efficient Turbo Product Codes
No full textIn this letter, a turbo product code (TPC) is combined
with multilevel modulations (8-phase-shift keying and
16-quadrature amplitude modulation). The component codes are
Bose–Chaudhuri–Hocquengem (BCH) or extended BCH. We
derive soft-input/soft-output modules based on the dual code,
with exact Euclidean metrics, and we show that the iterative TPC
decoder gains no advantage in performance from this. Next, we
evaluate asymptotic approximations for maximum-likelihood
(ML) decoding from a combinatorial approach that can be applied
to any bit-interleaved multilevel modulated code, once the first
term (or terms) of the Hamming weight spectrum are known.
For the TPCs and modulations studied in this letter, random bit
interleaving before modulation leads to improvedML asymptotes.
Simulations confirm that this advantage is maintained also under
iterative decoding
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