信道编码LDPC和Turbo.docx

Simulation of channel codingTask1: Some of the lines in the function are not commented. Add comments to explain them.See Appendix 2.Task2: Draw a block diagram that describes the action of this function.Figure 1 qpsk_turboTask3: Write a script that uses the function to plot the simulated BER of the transceiver as a function of the energy per bit to noise power spectral density ratio (Eb/N0). Discuss the results.The results are shown blow. As we can see, when EbN0 is small, BER changes slowly, when EbN0 is large, BER change fast. This is because when EbN0 is small, the number of error bits is too much, turbo code cannot be effective error correction, and when the signal to noise ratio is large, the number of error bits reduced, turbo code can be effective error correction , BER quickly reduced.Figure 2 BER of turboTask4: Increase the number of iterations in the turbo decoder (use three additional values). Plot on the same figure the BER curve for each value. Comment on the results.Figure 3 BERs under different iterationsAs we can see, with the increase in the number of iterations, BER performance is getting better and better. This is because the more the number of iterations, the better the performance of the turbo code. It should also be noted that the more the number of iterations, the slower the decoding, the less the relative performance gain.Task5: Replace the turbo coder by an LDPC coder. Plot the BER and comment on the results.Figure 4 BER of LDPCIn this part, the code rate is 1/3 and the length of message bits is 21600. The parity-check matrix of the LDPC code with code rate 1/3 is from the DVB-S.2 standard.As we can see, when EbN0 is small, BER changes slowly, when EbN0 is large, BER change fast. At the same time, it can be found that LDPC performance at this time is better than turbo. This is because the longer the message bits are, the larger the coding gain. In this section, the length of the message bit is 21600, far greater than 2048.Task6: LTE uses a t