GENERATING PSEUD ORANDOM CODES

Autor/autori: PhD Student Ion POPA

Rezumat: In aceasta lucrare este prezentata o modalitate de generare a codurilor de imprastiere utilizand programe realizate in Matlab. Pentru studiu am luant in considerare trei tipuri de secvente de cod : secventa M ,secventa Gold si secventa Gold ortogonal ,iar pentru fiecare secventa de cod am realizat cate un program in Matlab. Aceste programe sunt notate in lucrare astfel: „create_ sequence_ M ”and „ create_ sequence_ gold „. Pentru validarea acestor secvente am realizat doua programe : autocorrelation_ type_ M" „si „correlation_ type_ M „. Cu ajutorul programului „autocorrelation_ type_ M” se poate calcula functia de autocorelatie pentru fiecare secventa de cod iar cu programul „correlation_ type_ M ” putem verifica daca doua secvente de cod indeplinesc conditiile de „pereche preferata”. Aceste programe sunt necesare atunci cand dorim sa ralizam studii de performanta pentru sisteme de comunicatii mobile care folosesc tehnologia CDMA

Cuvinte cheie: functia de autocorelatie , functia de corelatie , secventa M, secventa Gold si secventa Gold ortogonal

Abstract: This paper presents a method of generating pseudorandom codes, using programs made in Matlab. For this study, we considered three types of code sequences: M sequence, Gold sequence and orthogonal Gold sequence and for each code sequence we realized one program of generating in Matlab. This programs are noted: ”create_ sequence_M” and „create_sequence_gold”. For validation of these sequences we realized two programs: “autocorrelation_ type_ M ” and “ correlation_ type_ M ”. Using the ”autocorrelation_ type_ M” program it can be calculated the autocorrelation function for each code sequence which was generated and using the “correlation_ type_ M ” we can calculate the correlation of code sequence and we can verify which of the code sequence satisfy the “preferred pair”conditions. This programs are very important when we want to realize performance study for mobile communication system, which uses the CDMA technology.

Keywords: autocorrelation function, cross-correlation function, M sequence, Gold sequence, orthogonal Gold sequence

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