Analysis of several solutions on F-band interference problems

Introduction of F-band In China, the F-band is currently divided into 1880MHz-1920MHz, *** there is a 40M bandwidth. Existing F-band due to the small smart phone network has not yet been withdrawn from the market, 1900MHz-1920MHz 20M frequency bandwidth temporarily can not be used. In the large-scale experimental network of TD-LTE currently carried out by China Mobile, Guangzhou, Shenzhen and Hangzhou are mainly deployed on the basis of F-band, while other cities as a whole are mainly deployed on the basis of D-band. In this band and its neighboring bands, it also contains part of GSM1800 network, TD-S network and a few PHS networks. although the bandwidth of F band is very limited compared with that of D band, however, its importance, resources and market significance in the construction of TD-LTE project of the mobile exists objectively, and the mixed grouping of D+F network in the industry has already reached a **** knowledge. Whether within the mobile group or the major suppliers are very important in the F-band paving network building station, there is no need to repeat here. However, in the face of the recent hotly debated F-band new construction or upgrade debate, is it inclined to more new stations, or more upgraded stations? In this paper, we will mainly discuss the differences and characteristics of the specific realization scheme of F-band construction from the technical point of view and the relevant level of project implementation. Other factors affecting the evaluation of different networking solutions in F-band will not be discussed here.Core Problems of F-band In the future construction of TD-LTE commercial network of mobile, the core problem of F-band application is undoubtedly how to solve the interference problem. In addition, there are problems such as engineering implementation difficulty and project construction cycle. Mobile's TD-L experimental network construction in many first and second tier cities has been very large, and some important cities have also expanded the scale of experimental network. The project data and test results from each Trial site are already abundant. Therefore, the time is ripe to explore the advantages of new construction and upgrading of their respective technologies. After analyzing and summarizing the types of interference in TD-L experimental networks in many places, the main interference comes from the following aspects: second harmonic interference in the GSM900MHz band, third-order intermodulation interference in the GSM1800MHz band, interference introduced by the insufficient blocking capacity of the existing TD-S network equipment in the F-band, interference introduced by the varying degrees of neighboring-frequency interference in PHS networks, and spurious interference in the GSM1800MHz band. These interference problems have long been foreseen, and in the early experimental network testing of the main manufacturers of the network to obtain data collection and verification. From the experimental network test in a second-tier city, it was found that the antenna feeder part of the GSM network of some manufacturers was old, with different degrees of deterioration, generating strong second-harmonic interference, while the PHS base station would cause large neighboring-frequency interference in some areas. In contrast, the outfield test in Guangzhou found that the existing mobile TD-S network has low anti-blocking capability and some spurious interference. These complex interferences will lead to a deterioration of SINR and a significant reduction in network throughput, at which point the expected high throughput cannot be achieved even if the RSRP (Reference Signal Received Power) is high.