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Type of Document	Dissertation
Author	Feng, Hanying
Author's Email Address	hanying AT caltech.edu
URN	etd-05232002-173821
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-05232002-173821
Title	Rate loss of network source codes
Degree	PhD
Option	Electrical Engineering
Advisory Committee	Advisor Name Title Michelle Effros Committee Chair Jehoshua (Shuki) Bruck Committee Member Robert J. McEliece Committee Member Steven Low Committee Member Yaser S. Abu-Mostafa Committee Member
Keywords	multiterminal source coding rate-distortion function lossy data compression tree-structured vector quantizer
Date of Defense	2002-05-06
Availability	unrestricted
Abstract In this thesis, I present bounds on the performance of a variety of network source codes. These rate loss bounds compare the rates achievable by each network code to the rate-distortion bound R(D) at the corresponding distortions. The result is a collection of optimal performance bounds that are easy to calculate. I first present new bounds for the rate loss of multi-resolution source codes (MRSCs). Considering an M-resolution code with M>=2, the rate loss at the ith resolution with distortion D_i is defined as L_i=R_i-R(D_i), where R_i is the rate achievable by the MRSC at stage i. For 2-resolution codes, there are three scenarios of particular interest: (i) when both resolutions are equally important; (ii) when the rate loss at the first resolution is 0 (L_1=0); (iii) when the rate loss at the second resolution is 0 (L_2=0). The work of Lastras and Berger gives constant upper bounds for the rate loss in scenarios (i) and (ii) and an asymptotic bound for scenario (iii). In this thesis, I show a constant bound for scenario (iii), tighten the bounds for scenario (i) and (ii), and generalize the bound for scenario (ii) to M-resolution greedy codes. I also present upper bounds for the rate losses of additive MRSCs (AMRSCs), a special MRSC. I obtain two bounds on the rate loss of AMRSCs: one primarily good for low rate coding and another which depends on the source entropy. I then generalize the rate loss definition and present upper bounds for the rate losses of multiple description source codes. I divide the distortion region into three sub-regions and bound the rate losses by small constants in two sub-regions and by the joint rate losses of a normal source with the same variance in the other sub-region. Finally, I present bounds for the rate loss of multiple access source codes (MASCs). I show that lossy MASCs can be almost as good as codes based on joint source encoding.
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