Click here  to download a DOS demo (called tcdemo.exe) of the turbo code used by the UMTS/WCDMA/3GPP third generation cellular system. This demo was built from our stand-alone C decoder implementation. The code and its decoder are documented in the following paper: M.C. Valenti and J. Sun, “The UMTS turbo code and an efficient decoder implementation suitable for software defined radios,” Int. J. Wireless Info. Networks, vol. 8, no. 4, pp. 203-216, Oct. 2001.

Not sure what parameters to use? The first time around you may want to enter the following:
Welcome to the UMTS Turbo Code demonstration
Copyright 2001, Matthew C. Valenti
Contact info-at-iterativesolutions.com for licensing information

Enter frame/interleaver size: 1000
Enter 0 for AWGN channel and 1 for Rayleigh fading: 0
Enter value of Eb/No (in dB): 0.65
Enter decoder type

0 for linear-log-MAP
1 for max-log-MAP
3 for log-MAP using piecewise linear approximation
4 for log-MAP using C-function calls

: 0
Enter number of decoder iterations: 10
Enter seed for random noise generator (int): 0
Enter seed for random data generator (int): 0
Enter number of frames to process: 100

Running UMTS Turbo Code demonstration
EbNo = 0.65 dB

DEMO results

Iteration 1: BER = 0.088140
Iteration 2: BER = 0.033690
Iteration 3: BER = 0.012370
Iteration 4: BER = 0.004600
Iteration 5: BER = 0.002240
Iteration 6: BER = 0.001310
Iteration 7: BER = 0.000730
Iteration 8: BER = 0.000360
Iteration 9: BER = 0.000030
Iteration 10: BER = 0.000000
Data Rate = 83963 bps
Average number of decoder iterations = 2.920000