Performance Prediction of a Turbo-coded Link in Fading Channels

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Volume Title

Elektroniikan, tietoliikenteen ja automaation tiedekunta | Master's thesis

Date

2010

Department

Major/Subject

Tietoliikennetekniikka

Mcode

S-72

Degree programme

Language

en

Pages

78

Series

Abstract

Channel coding is the method of adding redundancy to the data in order to reduce the frequency of errors or to increase the capacity of a channel. Turbo codes are the most superior class of codes making achievable channel capacity almost at par with the Shannon limits. In Adaptive Modulation and Coding (AMC) the prediction of error performance of a channel is an important step before choosing one of the Modulation Coding Scheme (MCS). Since in Turbo-coded system we donot have analytical relations to relate error performance with the Signal to Noise Ratio (SNR). Therefore, normally simulation results are stored in the form of the look up tables. In this work we propose an error performance prediction model for a BPSK modulated Turbo-coded link. This model predicts performance addressing the fading phenomena for wireless radio channels. It takes the large variations in the SNR level within a code block into account along with the coding parameters. The SNR dB values profile inside a code block is considered in terms of their mean and variance. The model proposed is UMTS compliant and is continuous for values of the MCS code rate and the mean and variance of SNR dB values. It is an easier way of predicting link level performance as it replaces the discrete look up tables. Unlike the look-up tables it can be used for differentiation based analytical techniques used in system level optimization.

Description

Supervisor

Tirkkonen, Olav

Thesis advisor

Määttänen, Helka-Liina

Keywords

Fading, BLER, effective SNR, mean, variance, Turbo-codes

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