Randomization Effect of Errors by Means of Frequency-Hopping Techniques in a Fading Channel

This paper describes the effective randomization of errors by means of frequency hopping (FH) in a selective Rayleigh fading channel. The major advantage of the randomization is the option to use random error-correcting codes in burst error channels, including the fading channel. Bit interleaving, which operates in the time domain, is very useful to randomize the errors, but equivalent operation is possible by FH in the frequency domain. That is based on low correlation between frequency chips, which is realized by hopping over a sufficiently wide bandwidth in selective fading channels. In this paper, bit error rates of FH with majority decision are analyzed to show the effect of randomization in various spread bandwidths. It is also shown that FH and interleaving are equivalent in the sense that spread bandwidth corresponds to interleaving degree with respect to its randomization effect.