Rapid optimal scheduling for time-multiplex switches using a cellular automaton
Christopher James Rose · IEEE Transactions on Communications · 1989
Many time-multiplex switching systems require that the incoming traffic be scheduled to avoid conflict at the switch output (two or more users converging simultaneously upon a single output). Optimal scheduling provides a means to assign traffic on demand such that either blocking probability is minimized (unbuffered system) or packet waiting time is minimized (buffered system). However, computation of an optimal schedule for switches of a reasonable size (i.e. N=100) may require many seconds or even minutes, whereas the traffic demand may vary much more rapidly. Since the computation time varies as O(N/sup 2/), the problem becomes readily intractable for large N. This computational bottleneck is overcome by using a scheduling algorithm which is run on a simple special-purpose parallel computer (cellular automaton). A schedule is produced in O(N) time if signal propagation time in the automaton is considered negligible, and therefore increases in computation speed by several orders of magnitude should be possible; the time to compute a schedule for a 1000-input switch would be measured in milliseconds rather than minutes.>