The purpose of the work is the theoretical and experimental study, with the use of simulation in Matlab, the performance of a digital telecommunication system. We consider it below Digital Telecommunication System model A sequence of bits appears at the input of the system. To improve its performance system, based on the average bit error probability criterion, you will implement a simple channel coding which is repetition coding. According to her repeating the same bit of information multiple times. Specifically, every bit that reaches the encoder input is repeated N times (where N ϵ {1,3,…,}). The output of the encoder goes as an input to the digital modulator where the matching is done of the input bits to the input symbols, in the following way Bit Symbol
0 +𝐴
1 -A 𝑃𝑒 = 𝑄 (√ 𝐸𝑠/ 𝜎𝑤 ^2 ), 𝐸𝑠 = 𝐴 2 , PΒ = Pe Next, demodulation takes place where the received symbols are mapped to bit using the previous table. In the end, her procedure is carried out decoding according to which in each N symbols used during coding, the number of aces and zeroes is counted and a decision is made in favor of the digit that appears most times. To calculate the mean (experimental) bit error probability (BEP) relation can be used PB = Fe/ 2 Note that Es=2Eb, where Eb is the average bit energy. For the corresponding mean calculation of bit error probability using coding you will use the previous relation to combined with the fact that a Binomial random variable is created. Specifically, we have one sequence of N independent Bernoulli trials with an equal probability of "success" in each of them with PB. Need to calculate the cumulative probability of ⌈ occurring 𝛮 /2 ⌉,⌈ 𝛮 /2 ⌉ + 1, … , 𝛮 bit errors. Finally note that (𝑆𝑁𝑅)𝑑𝐵 = 10𝑙𝑜𝑔10 ( 𝐸𝑠/ 𝜎𝑤 ^2)
