An extended cutoff rate for frequency-hopping communications with non-ideal interleaving

Summary form only given. The suitability of the capacity C and the cutoff rate R₀, which are the customary measures for evaluating the channel's ability to transmit information reliably, turns out to be questionable with respect to frequency-hopping communications over channels with partial-band jamming and nonideal interleaving. More explicitly, nonideal pseudorandom block interleaving is assumed, resulting in a block interference channel with a noise severity level that depends on the number of jammed hops in each block of interleaving. As the interleaving span increases, R₀ for this channel departs, inadequately, from the cutoff rate for the memoryless channel. Also, C does not reflect the behavior of the channel when short block codes, those usually encountered in interleaved communications, are used. An extended cutoff rate R_0e for channels with block memory has been obtained. Expressions for the extended cutoff rate have been derived in both the presence and absence of side information. As the interleaving span tends to infinity, R_0e converges asymptotically and apparently monotonically to R₀ for the memoryless case.