We consider the problem of designing scheduling algorithms for the downlink of cellular wireless networks where bandwidth is partitioned into tens to hundreds of parallel channels, each of which can be allocated to a possibly different user in each time slot. We prove that a class of algorithms called Iterated Longest Queues First (iLQF) algorithms achieves the smallest buffer overflow probability in an appropriate large deviations sense. The class of iLQF algorithms is quite different from the class of max-weight policies which have been studied extensively in the literature, and it achieves much better performance in the regimes studied in this paper. Categories and Subject Descriptors C.2.1 [Computer-Communication Networks]: Network Architecture and Design—Wireless Communication General Terms Algorithms, Performance Keywords Scheduling algorithm, large deviations, delay optimality