Serbest Uzay Optik Haberleşme Sistemlerinde Turbo Çarpım Kodların Performans Analizi

Öz

Bu makalede, turbo çarpım kodlarının(TPC) serbest uzay optik(FSO) sistemlerinin performansa olan etkisi incelenmiştir. Atmosfer modeli olarak log-normal dağılım seçilmiştir. MATLAB benzetim çalışmaları zayıf ve orta türbülansta gerçeklenmiştir. Turbo çarpım kodlarını oluşturan kod bileşenleri, genişletilmiş hamming ve genişletilmiş Bose–Chaudhuri–Hocquenghem(BCH) kodları olark kullanılmıştır. Benzetim sonuçlarına göre, özellikle orta türbülans altında TPC kullanımı ile hedeflenen bit hata oranına(bit error rate(BER))ulaşırken 15dB’ye kadar kod kazancı sağlanabilmektedir. Bu kod kazancı BCH tabanlı TPC kullanılırsa daha fazla iken hamming tabanlı TPC kullanılırsa daha az olmaktadır. Düşük kod oranlı ve BCH kod bileşeni ile oluşturulan TPC ile 0dB sinyal-gürültü oranı(signal to noise ratio(SNR)) değerinde bile sistemin BER’i 10^-5 ’e düşebilmektedir.

Anahtar Kelimeler

• Turbo çarpım kodu,serbest uzay optik,bit hata oranı,atmosferik türbülans

Performance Analysis of Turbo Product Codes on Free Space Optics Communication Systems

Öz

Inthisarticle, theeffect of turbo productcodes(TPC) overtheperformance of freespaceopticssystems is analyzed. Log-normal distribution is selected as theturbulence model. MATLAB simulationsarecarriedout in weak and moderate turbulence. Component codes which construct turbo product codes are used as extended hamming and extended Bose–Chaudhuri–Hocquenghem(BCH) codes. According to simulation results, it can be provided that up to15dB code gain to reach the target bit error rate(BER) with the use of TPC especially under moderate turbulence. While this code gain is more if BCH based TPC is used, it becomes less if hamming based TPC is used. With low code rate and TPC which is constructed with BCH codecomponent, BER of system can decreaseto even in 0dB signal to noise ratio(SNR).

Anahtar Kelimeler

• Turbo product code,free space optic,bit error rate,atmospheric turbulence

Kaynakça

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