Research On Coexistence Of LTE System And NGB System In The Same Frequency Band

Since the 3GPP started project of LTE, it has frequent meetings to promote the study of LTE. However, any kind of wireless communication technologies are impossible from dependence on spectrum resources, spectrum allocation is directly related to the application and development prospects of the communication technology. In order to fully utilize the limited radio spectrum resource, it is necessary to ensure that the wireless communication system operating in the same geographical area has a good electromagnetic compatibility when Adjacent coexist. Band below 1GHz has a good wireless performance and high coverage,which is the most popular LTE band,but this band has been used by 2G,3G mobile communications, broadcasting, navigation, and other radio services,so it is occupied very crowded. On the other hand, with the digitization of broadcast television system, a portion of the spectrum will save resource, this part of the resource is called digital dividend. IN different countries and regions, the size of the digital dividend is also different, Chinese digital dividend band for "698MHz-806MHz"(referred to 700 MHz band). This band may be used by LTE. So when this band is used, it will appear that the same geographical location LTE system and other wireless communication systems coexist, at this time it will cause the presence of adjacent channel interference problems. Researching evaluation adjacent channel interference and looking for appropriate measures to reduce adjacent channel interference ensure the two systems coexist which has become a very important issue.This paper analyzes the interference between LTE systems and NGB system in the 700 MHz,it has total of four scenarios which includes NGB system interference LTE uplink, NGB system interference LTE downlink, LTE uplink interference system NGB systems, LTE system downlink interference NGB system,as to NGB launch system suffered minimal external interference,so it is not considered. According to the technical features of systems and associated interference control techniques used in the LTE system, it will establish model which simulates with two adjacent frequency coexistence system interference in a variety of scenes from a deterministic analysis of interference and a reasonable assessment of the degree. Finally, it will have the value of ACIR which makes systems coexist in the condition of cities and suburbs with Monte Carlo simulation method, then draw the corresponding simulation curve, given a variety of spatial and frequency domain isolation between the two systems coexist adjacent channel interference scenarios combined with performance parameters of the two systems, finally given propose appropriate measures to avoid the interference.