On The Adjacent Channel Interferencein Ultra Dense Deployment

Abstract: The giant ever increasing demand for higher data rates and better Quality of Service (QoS) is rapidly growing and operators’ main concern is to supportthe growth of mobile data traffic and address the users’ expectations whileat the same time keeping the costs of services reasonable [1], [2], [3]. This is more vital in residential and dense urban areas where the reception of themacro signal level becomes weak [4]. Therefore, the implementation of ultradense networks becomes a promising approach which is expected to providegood indoor coverage and higher capacity in residential areas. Nevertheless, the potential degradation of network performance due to severe interferenceoriginated from nearby networks should be deeply studied prior to full-scaleimplementation of ultra dense networks. The main concern of this thesiswork is to investigate the coexistence between two operators in Time DivisionDuplex (TDD) system which are using adjacent frequency channelsand implemented in the same geographical area. For this purpose, the systemlevel simulation based on Monte Carlo method is performed to revealthe impact of critical parameters including Adjacent Channel Interferencepower Ratio (ACIR), Uplink-Downlink synchronization between operators, Base-Stations positioning, and Internal walls existence on the system performance. Afterwards, the effect of densification on the previous findings isstudied. Results show that in downlink and uplink, approximately 30 dB and55 dB of ACIR is required, respectively, in order to eliminate the impactof adjacent channel interference. Furthermore, in uplink, synchronizationis necessary when base stations of operators are collocated. In downlink, however, synchronization and collocation is beneficial when signal quality ispoor. On the other hand, it is shown that densification is feasible providedbase stations employ adjustable transmission power model. Moreover, internalwalls can improve system performance due to attenuation of interferencesoriginated from surrounding cells.