Search Engine

Convolutional Encoding

Add Question

20 Threads found on Convolutional Encoding
hello everyone, I have used convolutional encoding with qpsk modulation using AWGN channel. During decoding if the signal to noise ratio is less than 5 like 1, 2 etc. It shows error i.e. ??? Error using ==> vit Invalid input for chosen decision-type. Allowed input values for hard-decision decoding are 0 and 1. But if keep
Im doing a matlab code on OFDM using concatenated RS-CC. The coding is RS(255,239,8) act as inner coding and rate 1/2 constrain length 7 polynomial (171,133) convolutional code act as outer coding. I couldn't get after reed solomon encoding. can u plz help me to write this coding.
Hi, When decoding of a message using vitdec I end up with 3 more bits ,well I know that they are 3 because I have 3 registers ,but how to nicely get rid of these bits OR how to balance them? I tried tailing the input message with 3 0's but I ended up with more 3 bits again. :?:
Dear all. I have a question regarding the different modulation type and their relationship with the convolutional channel encoding.. why does the lower order modulation formats (BPSK ...) have their BER graph more towards the lower Eb/No (dB) compared to higher order modulation formats e.g. (64 QAM..)? thanks
Matlab simulation of convolutional encoding and decoding, including 1/2, 2/3 3/4 - Source Codes Search Engine -
Hi i have some questions please. I want to calculate the theoretical bit error rate for my chain of communication and i need to know the relationship between Es/No and Eb/No for a coded system. is that these relationships are just and valid for all digital modulation schemes and encoding types (convolutional coding, RS, turbo-code, arq, ..
i have implemented a code for puncturing coding with rate =2/3 (i use the encoding in watermarking) the problem that the output is null when tb is high the puncturing is t = poly2trellis(3,); v=convenc(msg,t, ); and the depuncturing and decoding is vitdec(mes_recu,t,tb,'cont','hard',) i don't understand why the o
Hello, I have tried to simulate the performance of an OFDM system using QPSK a rate 1/2 convolutional code and a Viterbi decoder at the receiver. The problem I face now is after plotting the results, I come up with a funny graph that doesn't look anything like the theoretical result. Here's an attachment of the MATLAB image i obtained. Can an
How do you determine traceback length in convolutional coding?Is traceback length 5 times the constraint length.If so,i am using convolution encoding (7,)den te traceback length would be 35.then there is null error rate which is impracticable
jst need sumone to help me in getting convolutional encoding program in C/C++ or in MATLAB .plz tell me how can i implement it on a DSP kit
i jst need to implement convoultional encoding that is programmed in C language or in MATLAB .how can i implement using a dsp kit.
I am doing a matlab simulation on QPSK mod and demod passing thru AWGN channel. I am double encoding my signals to get better performance. The coding is RS(31,27) act as outer coding and rate 1/2 constrain length 7 polynomial (171,133) convolutional code act as inner coding. After doing all these with QPSK demod, I could not get the expected BER. M
simply speaking, hard decision is to decide the output of modulation to be 0 or 1. soft decision give more bits to quantize the output. I am a little puzzled with puncturing in viterbi algorithm. What's the difference bwteen soft/hard decision. Soft decision, bits->1/2 convolutional encoding->QPSK---->Demod->quantize t
these three steps are performed in following order crc convolutional encoder block interleaver
If you understand convolutional coding you should try reading C. Berrou's paper, he proposed turbo codes explaining why they use recorsive systematic encoder and interleaving. Try some research on the MAP algorithm and the concept of soft output decoders. Interleaving gets very important when concatenating convolutional codes. Mario.
The Vierbi deocder in the Miwax is a Tail biting-convolutional encoding, therefore, special processing is needed for the viterbi decoder since the initial state is unknown at the decoder.
Hello friends, here is the code of convolutional encoding and decoding, convolutional encoding is simple enough, but the logic in decoding is not understandable. can u tell me what logic is he putting here. convolutional encoder: UINT16 SR = 0; UINT16 uPoly1 = 11001; UINT16 uPoly2 = 11011; UINT8 (...)
the 3 parameters in convolutional encondin are k=number of input bits n=number of output bits m=number of memory registers k/n is code rate,constraint length=?? in some sites constraint length is given as k*(m-1) and in some sites it is given as k*m kindly tell which one is correct
Is there any tool to 1. enter a state machine and simulate 2. enter a convolutional encoder as a G and simulate encoding or 3. capture as a Trellis 4. Convert these and link with MATLAB 5. Is ADS capable of these things... any suggestions please... thank you
I'm simulation BPSK with convolutional encoding in Simulink. I use the Error Rate Calculation block to calculate the delay between Tx and Rx. The error rate block contains a recieve delay parameter which has to be inserted with the value of the delay between its 2 inputs. I used the Find delay block to find the delay between Tx and Rx, however i