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Implementation of parallel Reed-Solomon Turbo Decoder
Objective
 Implementing RTL code for RS turbo decoder.
 To achieve high efficiency.
 To achieve high Throughput
Overview
 Implementing RS turbo decoder using VHDL code.
 Introduce errors.
 Detecting the errors.
 Correct the errors.
RS Decoder
 Syndrome computation (S C ).
 KEY (Key- equation- solver).
 CSEE (Chien search Error evaluator ).
Architecture
Pseudo code for RS decoder
 1 : Introduce errors fSimulate noiseg
 2 : Compute Syndromes
 3 : if S(x) = 0 then
 4 : Declare no error
 5 : else (Error in code word)
 6 : {Key Equation Solver}
 7 : for all j such that do
 8 : if = 0 then {Chien Search}
 9 : Compute Yi {Forney Evaluator}
 10 : Add Yi to the received symbol.
 11 : end if
 12 : end for
 13 : end if
 14 : Compare the output with the original code word
K E S
 Generates the key equation
 Error locator
 Error evaluator
The two polynomial defined as
 The syndromes are used to compute the error locator and error evaluator polynomial.
 If there are e errors in the received code word, we can define the error locator polynomial of degree e and the error evaluator polynomial of degree at most e − 1 to be
Chien Algorithm
 Chien search involved checking whether for each j,
 If it is, then an error has occurred at j th location in the received code word.
Error Evaluator
 The next step is to compute the value of error, Yi that has occurred.
 This is computed by Forney’s error value formula :