I have the following outputs at the various iterations in Turbo Equalization. Iteration No. 1 -> Error at the output of BCJR = 16, Error at the output of ECC= 105 Iteration No. 2 -> Error at the output of BCJR = 8, Error at the output of ECC= 51 Iteration No. 3 -> Error at the output of BCJR = 6, Error at the output of ECC= 88 Iteration No. 4 -> Error at the output of BCJR = 6, Error at the output of ECC= 48 Iteration No. 5 -> Error at the output of BCJR = 6, Error at the output of ECC= 94 Now, in the third iteration, the error at the output of BCJR is lower than previous iteration but error at the output of ECC is higher? My question is whether the iterations in the turbo equalization should ALWAYS improve the performance or we can have such sequences of error count in which the output as shown above can happen. I am debugging my code and don't know whether I should track it down to a bug or it is an expected output. The implementation involves a thresholding of LLRs at the output of BCJR as well as ECC. I am thresholding the LLRs to remain in between 10 and -10. The BCJR implementation uses Jacobian method of approximating log(a+b). Can anyone direct me to a tutorial on equations that need to be implemented in BCJR? Thanks
Turbo Equalization
Started by ●October 31, 2011