  A fundamental challenge in wireless multicast has been how to simultaneously
achieve high-throughput and low-delay for reliably serving a large number of
users. In this paper, we show how to harness substantial throughput and delay
gains by exploiting multi-channel resources. We develop a new scheme called
Multi-Channel Moving Window Codes (MC-MWC) for multi-channel multi-session
wireless multicast. The salient features of MC-MWC are three-fold. (i) High
throughput: we show that MC-MWC achieves order-optimal throughput in the
many-user many-channel asymptotic regime. Moreover, the number of channels
required by a conventional channel-allocation based scheme is shown to be
doubly-exponentially larger than that required by MC-MWC. (ii) Low delay: using
large deviations theory, we show that the delay of MC-MWC decreases linearly
with the number of channels, while the delay reduction of conventional schemes
is no more than a finite constant. (iii) Low feedback overhead: the feedback
overhead of MC-MWC is a constant that is independent of both the number of
receivers in each session and the number of sessions in the network. Finally,
our trace-driven simulation and numerical results validate the analytical
results and show that the implementation complexity of MC-MWC is low.
