ABSTRACT
CONTENTS 12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 12.2 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
12.2.1 Broadcast Scheduling in Traditional Wireless Networks . . . . . 296 12.2.2 Broadcast Scheduling in CRNs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297 12.2.3 Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
12.3 System Model and Problem Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 12.3.1 Network Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 12.3.2 Interference Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 12.3.3 Problem Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
12.4 Broadcasting Tree and Coloring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 12.4.1 CDS-based Broadcasting Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 12.4.2 Tessellation and Coloring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
12.5 Broadcast Scheduling under UDG Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 12.5.1 MLBS under UDG Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 12.5.2 Analysis of MBS-UDG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
12.5.2.1 Broadcast Latency of MBS-UDG . . . . . . . . . . . . . 307 12.5.2.2 Broadcast Redundancy of MBS-UDG . . . . . . . . 313
12.6 Broadcast Scheduling under PrIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 12.6.1 Redundancy of MBS-PrIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
. . . . . . . . . . . 12.7.1 Broadcast Latency of MBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316 12.7.2 Broadcast Redundancy of MBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
12.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
12.1 Introduction Wireless spectrum is one of the most precious resources. With the rapid growth of the number of wireless devices, communications over the unlicensed spectrum bands become very crowded. On the other hand, the utilization of the spectrum assigned to licensed users varies from 15% to 85% according to the report from the Federal Communications Commission (FCC) [229], which is very inefficient. To alleviate the interference and collisions on the unlicensed spectrum, as well as to improve the efficiency of the licensed spectrum, researchers propose a new communication paradigm named Cognitive Radio Networks (CRNs), which enable unlicensed users to sense and learn the communication environment with an equipped cognitive radio, and opportunistically access the licensed spectrum without causing any unacceptable interference to the activities of licensed users [230].
