1,001 research outputs found
Zigzag Decodable Fountain Codes
This paper proposes a fountain coding system which has lower space decoding
complexity and lower decoding erasure rate than the Raptor coding systems. The
main idea of the proposed fountain code is employing shift and exclusive OR to
generate the output packets. This technique is known as the zigzag decodable
code, which is efficiently decoded by the zigzag decoder. In other words, we
propose a fountain code based on the zigzag decodable code in this paper.
Moreover, we analyze the overhead for the received packets, decoding erasure
rate, decoding complexity, and asymptotic overhead of the proposed fountain
code. As the result, we show that the proposed fountain code outperforms the
Raptor codes in terms of the overhead and decoding erasure rate. Simulation
results show that the proposed fountain coding system outperforms Raptor coding
system in terms of the overhead and the space decoding complexity.Comment: 11 pages, 15 figures, submitted to IEICETransactions, Oct. 201
Expanding window fountain codes for unequal error protection
A novel approach to provide unequal error protection (UEP) using rateless codes over erasure channels, named Expanding Window Fountain (EWF) codes, is developed and discussed. EWF codes use a windowing technique rather than a weighted (non-uniform) selection of input symbols to achieve UEP property. The windowing approach introduces additional parameters in the UEP rateless code design, making it more general and flexible than the weighted approach. Furthermore, the windowing approach provides better performance of UEP scheme, which is confirmed both theoretically and experimentally
Cyclone Codes
We introduce Cyclone codes which are rateless erasure resilient codes. They
combine Pair codes with Luby Transform (LT) codes by computing a code symbol
from a random set of data symbols using bitwise XOR and cyclic shift
operations. The number of data symbols is chosen according to the Robust
Soliton distribution. XOR and cyclic shift operations establish a unitary
commutative ring if data symbols have a length of bits, for some prime
number . We consider the graph given by code symbols combining two data
symbols. If such random pairs are given for data symbols, then a
giant component appears, which can be resolved in linear time. We can extend
Cyclone codes to data symbols of arbitrary even length, provided the Goldbach
conjecture holds.
Applying results for this giant component, it follows that Cyclone codes have
the same encoding and decoding time complexity as LT codes, while the overhead
is upper-bounded by those of LT codes. Simulations indicate that Cyclone codes
significantly decreases the overhead of extra coding symbols
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