Optimal transmission rate of coexistence beacon protocol in wireless regional area network

Abstract

Recently, numerous techniques in wireless environment have originated from the effort to increase the efficiency of scarce resources and one of techniques is Cognitive Radio (CR) technique which is especially based on practical approach. All frequency bands are not usually fully-utilized by users at a certain time, so CR technique temporally allows unlicensed users to utilize the unoccupied frequency bands at the condition of not interfering licensed users. The unoccupied frequency bands are called spectrum hole. Based on CR technique, standardization is also in progress which is Institute of Electrical and Electronics Engineers (IEEE) 802.22 Wireless Regional Area Network (WRAN). There are mainly two coexistence issues considered in the IEEE 802.22 WRAN standards. One is coexistence of incumbent users and unlicensed users and the other is called self-coexistence issue. In contrast with coexistence with incumbent, self-coexistence is caused by the overlapping among neighboring WRAN cells utilizing the same frequency bands. In this situation, WRAN cells can interfere with each other called inter-cell interference. To resolve the self-coexistence problem in the air interface, coexistence beacon protocol (CBP) is proposed for inter-base station (BS) communication, to avoid using the same channel in neighboring cells. In the thesis, we focus on the optimal transmission rate of CBP in WRAN environment. We investigate the properties of CBP transmission and find the tradeoff between throughput of users served by WRAN cells and the execution delay for channel selection. To find the optimal CBP transmission rate, we can come up with the reasonable objective function which takes both the throughput and execution delay aspect into account. The objective function reflects the property of CBP validated by simulations and finds easily the optimal CBP transmission rate under various situations.