  Admission control schemes and scheduling algorithms are designed to offer QoS
services in 802.16/802.16e networks and a number of studies have investigated
these issues. But the channel condition and priority of traffic classes are
very rarely considered in the existing scheduling algorithms. Although a number
of energy saving mechanisms have been proposed for the IEEE 802.16e, to
minimize the power consumption of IEEE 802.16e mobile stations with multiple
real-time connections has not yet been investigated. Moreover, they mainly
consider non real- time connections in IEEE 802.16e networks. In this paper, we
propose to design an adaptive power efficient packet scheduling algorithm that
provides a minimum fair allocation of the channel bandwidth for each packet
flow and additionally minimizes the power consumption. In the adaptive
scheduling algorithm, packets are transmitted as per allotted slots from
different priority of traffic classes adaptively, depending on the channel
condition. Suppose if the buffer size of the high priority traffic queues with
bad channel condition exceeds a threshold, then the priority of those flows
will be increased by adjusting the sleep duty cycle of existing low priority
traffic, to prevent the starvation. By simulation results, we show that our
proposed scheduler achieves better channel utilization while minimizing the
delay and power consumption.
