302 / 1971-01-01 00:00:00

Qos-aware Scheduling Scheme In Cognitive Radio Cellular Networks With Applications On Environmental Mornitoring

In a cognitive radio cellular network (CogCell), primary users (PUs) rarely utilize all the assigned
frequency bands in the given time period and the locations. The spectral inefficiency caused by the
spectrum holes motivated cognitive radio technology (CR) that presents unlicensed secondary users (SUs)
an opportunity for using spectrum holes. In this paper, we investigate the QoS-aware scheduling problem
defined in [14] in which all SUs will be scheduled to transmit in different time slots in order to guarantee the
QoS requirements from PUs. Note also that we planed to integrate the CogCell system into the existing
environmental monitoring platform to improve the communication efficiency and reliability. Moreover,
the data used in the CogCell are collected from different sensors deployed in the monitoring field. The
main objective here is to minimize the length of the scheduling process in terms of total number of the
time slots to admit all SUs a chance to transmit meanwhile the QoS requirements from both PUs and
admitted SUs should be guaranteed. This is a very challenging problem and the NP-hardness has been
shown in the literature [17]. Due to the limitations of centralized scheme proposed in [13, 14] in which the
topology of the CogCell and the sensor system has to be known in advance by both PUs and each SUs,
we focus on decentralized (distributed) approaches and propose a time efficient scheme to accomplish the
QoS-aware scheduling problem. To be our best knowledge, this is the first time to consider distributed
scheduling in CogCells with applications in the environmental monitoring.