  In this paper, we adopt a cross layer design approach for analyzing the
throughput-delay tradeoff of the multicast channel in a single cell system. To
illustrate the main ideas, we start with the single group case, i.e., pure
multicast, where a common information stream is requested by all the users. We
consider three classes of scheduling algorithms with progressively increasing
complexity. The first class strives for minimum complexity by resorting to a
static scheduling strategy along with memoryless decoding. Our analysis for
this class of scheduling algorithms reveals the existence of a static
scheduling policy that achieves the optimal scaling law of the throughput at
the expense of a delay that increases exponentially with the number of users.
The second scheduling policy resorts to a higher complexity incremental
redundancy encoding/decoding strategy to achieve a superior throughput-delay
tradeoff. The third, and most complex, scheduling strategy benefits from the
cooperation between the different users to minimize the delay while achieving
the optimal scaling law of the throughput. In particular, the proposed
cooperative multicast strategy is shown to simultaneously achieve the optimal
scaling laws of both throughput and delay. Then, we generalize our scheduling
algorithms to exploit the multi-group diversity available when different
information streams are requested by different subsets of the user population.
Finally, we discuss the effect of the potential gains of equipping the base
station with multi-transmit antennas and present simulation results that
validate our theoretical claims.
