Spectrum sharing of the international mobile telecommunication-advanced and digital broadcasting in the digital dividend band

摘要

Increasing demand for wireless services has recently led to a radio spectrum shortage. As the spectrum is a limited and scarce natural resource, it should be used as efficiently as possible. In this thesis, a spectrum sharing study is conducted between the Digital Broadcasting (DB) and International Mobile Telecommunication-Advanced (IMT-A) in the 470–862 MHz band. First, a spectrum sharing simulation model based on statistical methodology is proposed in order to identify the requirements for co-existence between IMT-A and DB systems. The results show that co-existence is possible for a limited number of adjacent channels and for a specific sharing scenario. Next, a spectrum sharing analytical model is developed based on the enhancement of a current coexistence model that has been widely used in spectrum sharing research. From this, it is seen that when the DB bandwidth is 8 MHz, a higher IMT-A bandwidth (20 MHz) can co-exist more feasibly with DB than a lower IMT-A (5 MHz) bandwidth. Moreover, in deploying these systems in urban areas, the required separation distances decrease. We then propose an analytical method for evaluating potential compatibility of cognitive radio (CR) systems. This method computes the allowed maximum in-band (PIB) and out-of-band (POOB) transmission power of a CR system based on a victim receiver interference criterion. The PIB and POOB achieved are 16.41 dB higher and 23.76 dB lower, respectively, than those achieved in the traditional method. Finally, we propose a system called Wireless Link using the Global Communication Channel (WLGCC) that enhances spectrum sharing between DB and CR systems within the licensed 470–790 MHz band. The results show that WLGCC does not degrade existing DB service while reliably transmitting information on vacant frequency bands to the CR.