Improvements encoding energy benefit in protected telecommunication data transmission channels

The paper make the following statements: turbo-codes are formed as result of composing two or more component codes, which are variants altering one data sequence; and decoding procedure consists in transmitting soft scheme of decision making from output of one decoder to input of another one and repeating this procedure until the reliable decision. It has been defined that enhancing noise resistance in digital telecommunication channels is achieved by using schemes of cascade turbo-encoding. The slope of TC characteristics is defined to lower at growing value of Eb / N0 , what testifies of saturation effect in error probability. From the research it has been found that encoding energy benefit (EEB) for cascade code is formed by the structure: outer Reed-Solomon encoder, inner –turbo-encoder makes about 1.8 dB for level BER 10E-6 as compared with cascade code CC: RS (255, 223), CnC (171, 133), BPSK, R=1/2. The structural scheme of data transmission channel with cascade turbo-encoding has been developed. It is defined that in case of encoding rate ½ EEB=2.3 dB (BER=10E-5) as compared with cascade code having the following structure: SCS RS (255, 247), interleaver, CnC (171, 133), QPSK, R = 1/ 2 . In case of realizing data transmission channel at encoding rate 1/3 - EEB equaled 2.8 dB (BER=10E-5), as compared with cascade code having structure: SCS RS (255, 247), interleaver, CnC (171, 133), QPSK, R = 1/ 2 . Changing code structure, encoding rate in case of turbo-encoding leads to increasing EEB. It has been developed Simulink –simulation model for data transmission with cascade turbo-encoding with the purpose to research encoding effectiveness for protection from errors in digital telecommunication channels.The features of using noise resistant encoding for protection from errors in digital data transmission channels with phase modulation have been analyzed. The building principles and encoder and decoder schemes of turbo-code were observed. The digital data transmission system with outer and inner turbo-encoder has been developed. The recommendations to type and structure of cascade encoder components have been given. Analytical relationships and research results describing bit error probability of cascade turbo-encoder components are represented. By using simulative modeling tools Matlab-Simulink the basic characteristics and features of digital transmission channel with cascade turbo-encoding and digital phase modulation were researched. The energy benefit gained by using cascade structures has been defined