Semester

Spring

Date of Graduation

2008

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Lane Department of Computer Science and Electrical Engineering

Committee Chair

Matthew C. Valenti.

Abstract

The performance of random error control codes approaches the Shannon capacity limit as the code length goes to infinity. When the code length is finite, then the code will be unable to achieve arbitrarily low error probability and a nonzero codeword error rate is inevitable. Information-theoretic bounds on codeword error rate may be found as a function of length through traditional methods such as sphere packing. Alternatively, the behavior of finite-length codes can be characterized in terms of an information-outage probability. The information-outage probability is the probability that the mutual-information rate, which is a random variable, is less than the code rate.;In this thesis, a Gaussian approximation is proposed that accurately models the information-outage probability for codewords of moderately short length. The information-outage probability is related to several previously derived bounds, including Shannon's sphere-packing and random coding bounds, as well as a bound on maximal error probability known as Feinstein's lemma. It is shown that the information-outage probability is a useful predictor of achievable error rate.

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