This document discusses using interleaving to combat burst errors in Reed-Solomon (RS) codes. It introduces interleaving as a technique that spreads long burst errors into random errors. The project tests increasing the code length and interleaving degree, finding that burst error correction improves when both are increased together. Increasing the error correction capability also increases bandwidth usage and encoding/decoding delays, so transmission rates must be considered. In conclusion, interleaving significantly reduces burst errors, with better performance from higher interleaving degrees and code lengths.

1. Burst Error Correction In RS Codes
Aditi Singal, Santosh Nagaraj
Electrical and Computer Engineering , San Diego State University
Introduction
• In communication systems the noise present in the channel are
generally assumed to be Additive White Gaussian Noise, which
has a Gaussian distribution. In real, the channel noise is not
always AWGN. Instead, the distribution of error is more complex
and the error rate varies over a range of time. Error correcting
codes improve the functioning and consistency of modern
digital communication system.
• Different FEC coding methods are used in the digital
communication systems. They are mainly classified into block
and convolutional codes [1-2].
• The aim of this project is to design a code that is efficient and
suitable to implement in wireless transmission systems
• The technique of interleaving a code is used to detect and
correct the burst error.
Project approach
• The general idea behind using interleaving is to spread the long
burst of error into random error.
• The simple interleaving can be achieved by using the degree of
interleaving denoted by λ , where λ -1 should be the multiple
of n.
• Interleaving is done by entering the data row wise in an
interleaver and taking a column wise output at the
deinterleaver.
Figure 1 A block interleaving system
Results
• Increasing the length of message bit for each block was
tested.
• Interleaving is the best way to combat burst errors because
Encoder and decoder uses shift registers
Decoder of interleaved code can be derived from the
d decoder of original code
• BER becomes better for the interleaving degree of 35 when the
length is 400. The code can correct more burst errors when the
length and degree of interleaving is increased at the same time
• Coding techniques with higher error detection and correction
capability will use more redundant bits and bandwidth. This
reduces information transmission rates and will increase the
delay for encoding and decoding at source and destination.
Thus, on the design of higher error correcting codes the factor
affecting the transmission rate should be wisely considered.
Figure 2 BER performance of interleaved RS codes
Discussions
• When the MATLAB code was implemeted for the project, it was
observed that the length of the code should be proportional to
the interleaving degree of the system
• If the error correcting capability of the code is greater than the
length of the codeword input, then the burst error cannot be
corrected by the interleaver..
• Burst Error correction capability depends on the length of the
code as well as the interleaving degree of the system.
• At the deinterleaver, the original data is obtained with the burst
error converted to random errors and spread thruoghout the
codeword length.
Concluding Remarks
• From the project, it is deduced that interleaving reduces the
burst error in transmitted data by a huge percentage.
• BER becomes better when the interleaving degree and code
length are increased simultaneously.
Reference
1. https://espace.cdu.edu.au/eserv/cdu:38795/Thesis_CDU_38
795_Rupakheti_S.pdf
2. Error Control Coding: Fundamentals and Applications (2nd
Edition) Textbook by Shu Lin, Daniel J. Costello