  We consider the joint scheduling-and-power-allocation problem of a downlink
cellular system. The system consists of two groups of users: real-time (RT) and
non-real-time (NRT) users. Given some average power constraint on the base
station, the problem is to find an algorithm that satisfies the RT and NRT
quality-of-service (QoS) constraints. The RT QoS constraints guarantee the
portion of RT packets that miss their deadline are no more than a pre-specified
threshold. On the other hand, the NRT QoS is only to guarantee the stability of
their queues. We propose a sum-rate-maximizing algorithm that satisfy all QoS
and average power constraints. The proposed power allocation policy has a
closed-form expression for the two groups of users. However, the power policy
of the RT users differ in structure from the NRT users. The proposed algorithm
is optimal for the on-off channel model with a polynomial-time scheduling
complexity. Using extensive simulations, the throughput of the proposed
algorithm is shown exceed existing approaches.
