Study on coexistence and sharing between DVB-T and LTE system

Abstract

Coexistence and sharing between DVB-T and LTE-OFDM, at the same frequency band (662 - 742 MHz) with CR and without CR are presented. By increasing convention of digital TV, TV white spaces (TVWS) which are free spectrums after switch over will be remaining. Based on the opportunity of using these free spectrums for secondary users, we investigated the possibility of use them for LTE-OFDM. Our studied has shown that for coexistence and sharing between DVB-T and LTE-OFDM, probability of interference is high and large protraction guard distance is needed. However when we apply CR technique, it can avoid from harmful interference from secondary system and improve spectrum efficiency. CR technology is able to sense the spectrums over a frequency band, and detect the existence/absence of primary users, and base on detect the free spectrum; use that spectrum without harmful interference with primary users. So, the spectrum usage can be enhanced by making a secondary user access into the spectrum holes or spectrum parts that in an exacting position and time have not dedicated by a primary user. Our result shows that the probability of interference with CR will be decrees and the guard distance will be less than before. Also base on detection threshold (DT) (when we use CR technique), the number of active white space devices (WSDs) or secondary users changed when we use variable detection threshold. IN addition, the behavior of the LTE CR in downlink is closely to that of the measurement that has been introduced for uplink. The proposed project showed improvement of system with CR. Since the number of LTE users is growing and it is needed more spectrum and there are limitation in amount of spectrum, LTECR can be used by application as a future wireless communication system.