A Survey on Quality of Service (QoS) Provisioning for Multimedia Transmission in Cognitive Radio Networks (CRNs)
The gradual migration of today's wireless communication from one generation to the next (2G/2.5G/3G/4G) reflects the explosive growth of multimedia applications over the wireless Internet. But the significant bandwidth and stringent Quality of Service (QoS) requirement of multimedia transmission lead to a dramatic increase in the demand for radio spectrum. This phenomenon causes a critical challenge to the conventional Command-and-Control spectrum usage model, in which allowable spectrum uses are limited based on regulatory judgments. It is predicted that since the amount of useable spectrum is limited, as more services are added, there will come a time at which spectrum is no longer available for allotment.