Research On The Noise Model Of Wired Broadband Access Network Based On Statistical Theory

In view of the research on performance of wired broadband access network downstream channel, in order to ensure system quality in broadband access network, the study on performance of upstream channel has been a focus, especially noises’research.As well known, narrow-band continuous wave interference and impulse interference that are major reasons result in errors in a QPSK/16QAM modulated system on the upstream channel of broadband access network. So we should deeply research these noises in order to provide theory preparation for constructing the platform of three networks convergence.This thesis study wired broadband network configuration, noise signals in the upstream channel of broadband access network and signals’characteristics functions. Based on probability theory, probabilistic characteristics of the three combinations of the noises mentioned in the article are described. What’s more, probability density functions are derived. The relationship of bit error rate and probability density functions as well as Euclidean distance is used. Then the communication system platform of broadband access upstream channel is designed and constructed. The formula of bit error rate (BER) and the carrier-to-noise ratio(C/N) is obtained under a QPSK/16QAM modulated system on the upstream channel of broadband access network based on the noise with the relationship between bit error rate (BER) and carrier-to-noise ratio(C/N).In this thesis, the noise characteristic function model, the bit error rate and modulation error rate is the theoretical basis. Based on this, noises’probabilistic characteristics simulation model, modulation error rate (MER) simulation model and communication system simulation model are constructed. The impacts on system performance are analyzed and researched. Simulation results provide effective theories for enhancing system reliability.