系统外干扰无法接入网络优化实例

Optimization Examples on the External Interference Failing to Access Network

DCSl800的下行（1875MHz）与LTE的F频段（1880MHz）的保护带过小。导致DCSl800的下行对LTE的F频段（1880MHz-1900MHz）造成系统间干扰，由于是对LTE的上行频段形成干扰：故称为LTE的上行受到干扰。其主要表现在：前台测试发现，接入受到干扰小区的整体KPI都不高，影响上行吞吐率，UE发射功率高，干扰严重者，直接影响到该扇区的性能；系统测每个上行RB（0～99）的底噪高于正常值（正常为每个RB噪声-120dBm）。此种表现成因为：LTE与DC$1800基站共址；LTE与DCSl800天线的水平隔离度小于3米，垂直隔离度小于1米；解决方法为：退掉DCSl800的高频点，增加两者之间的保护隔离带；调整两者之间t天线的水平、垂直隔离度。

DCS1800 downlink（1875MHz） and LTE F-band（1880MHz） guard band is too small, causing sys- tem interference between DCS1800 downlink frequency bands and LTE F-band（1880MHz-1900MHz）. Be- cause the interference is in LTE uphnk bands, so call LTE uphnk interference. Its main features： reception test found that access to the overall KPI disturbed area is not high, affect the uphnk throughput, UE trans- mit power is high, impact directly on the performance of the sector. System testing each uplink RB（0-99） is higher than normal background noise （normal for each RB noise is -120dBm）. These cases are because： LTE base station co-located with DCS1800, LTE and DCS1800 antenna isolation level is less than 3 me- ters and vertical separation is less than 1 meter. Workaround： drain away DCS1800 high-frequency point - and increase zone between protective buffer, adjust T antenna between the horizontal and vertical isolation.