Channel coding for data storage and bandwidth efficient modulation for frequency-hopped multiple-access

Abstract

In this thesis, we consider an effective error-control coding for data storage system, and bandwidth efficient modulation for radio transmission system. The systems of interest are digital video cassette recorder (DVCR) and frequency-hopped spread-spectrum multiple-access (FH/SSMA) communication system. In digital VCR, multi-speed playback is one of the important function, including still, normal and high speed modes. For multi-speed play of digital VCR, we propose and analyze a new error-control coding scheme. Our scheme is shown to give a significantly improved performance over the conventional scheme with no increase in decoding time in normal play mode and with a little extra decoding time in high speed mode. A computer simulation is done on DCT-based quantized images corrupted by random errors to verify our analysis. It is found that the proposed scheme yields a significantly improved picture quality in normal as well as in high speed play mode. In FH/SSMA communication, M-ary frequency shift keying (MFSK) and Multicarrier on-off keying (MC-OOK) modulations are considered. For MFSK (M ≤ Q), we consider the system employs Reed-Solomon code over GF(Q) in Rayleigh fading channel. We investigate the tradeoff among the modulation symbol size (M), the number of frequency slots, and the code rate in maximizing the average number of successfully transmitted information bits per unit time and unit bandwidth (called normalized throughput). We find that it is desirable to use a large M in noise-limited environment. In interference-limited environment, it is more important to prevent errors (hits) by increasing the number of frequency slots than to correct them with forward error correction techniques or to reduce the error rate by increasing M. MC-OOK modulation is considered in FH/SSMA communication. The average bit error probability $P_b$ is analyzed in slow frequency-nonselective Rayleigh fading channel, and compared with that with MFSK under the constraint of fix...