Proc. ARR.L l&h Computer Netwotking Confctmce, 1991 LOSSLESS DATA COMPRESSION ALGORITHMS FOR PACKET RADIO W. Khmer, VE4WK DepNUNntofEkctricalandcomputerEngineering university of Manitoba Winnipeg, Mania CanadaR3T2N2 Fax: (204) 2754261 eMail:
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[email protected] Abstract that a decompressed file is the exact image of the source This paper is a review of important data coinpressicm file. This contrasts with data reduction and abstraction methods and techniques, showing their evolution from the techniques in which data are deleted from the source. simplest data suppression to the modem adaptive Neverthelas, such lossy data compression with fi-actals, (universal) methods. Selected lossless techniques for neural netwaks, and wavelets are important techniques for critically important da@ requiring perfect compression and research and practical applications, as they can achieve reconstruction are presented. Lossy techniques for impressive compression ratios as high as 10,OOO:l imperfect data such as speech, images, biological signals, ms9la]. and casual text are mentioned. There are many other techniques capable of 1. INTRODUCTION compressing and decompressing data efficiently [Stor88], weld87], [Lync85], megh81], [KinMa]. Which one is 1.1 Motivation suitable for a given data or fde structure? How should we measure the efficiency of the techniques? How easy is it Transmission of data over telephone lines and packet to implement them? These and other questions have to be radio, using standard data and file transfer protocols, as answered before using the best methods and techniques. well as storage of data on magnetic media and in other Therefore, the purpose of this paper is to provide a review storage devices can both be improved by data compression of the basic data compression methods and techniques, and techniques.