CICQ switches have been thoroughly studied in recent
years (see, e.g., [44], [45], [46]) and have been shown to possess
very good delay performance with only very simple scheduling
algorithms [44]. The scheduling in a CICQ switch is
decoupled into the input scheduling and the output scheduling.
The input scheduling result at time slot t is denoted as a
matrix MI
ðtÞ¼½MI
i;jðtÞNN , where if VOQi;j is selected to
send a cell, then MI
i;jðtÞ ¼ 1, otherwise MI
i;jðtÞ ¼ 0. Similarly,
the result of the output scheduling at time slot t is also a
matrix MOðtÞ¼½MO
i;jðtÞNN , where if CPBi;j is selected to
send a cell, then MO
i;jðtÞ ¼ 1; otherwise MO
i;jðtÞ ¼ 0. Unlike the
matchings in crossbar-based switches, MI
ðtÞ and MOðtÞ are
not necessarily permutation matrices, thus it provides more
flexibility in scheduling. The scheduling result of a CICQ
switch is denoted as MðtÞ¼½MI
ðtÞ; MOðtÞ, and its weight is
determined by MOðtÞ, which in turn is determined by MI
ðtÞ,
i.e.,