CDMA下行信号对EGSM上行信号的同频干扰研究

Research on the Same Frequency Interference on EGSM Uplink Signal from CDMA Downlink Signal

边境地区的CDMA网络的同频外部干扰是影响EGSM网络性能的主要因素之一。为此,以某国运营商的EGSM网络受到邻国CDMA网络的大范围强外部干扰为例,提出了一种排除EGSM网络外部干扰的解决方案。首先,从KPI指标统计和实际测试两个方面对CDMA干扰源进行了定位,确定出外部干扰源影响的强度及其影响范围。然后,采用Hata农村传播模型从理论上分析了CDMA干扰的影响程度和范围,并结合CDMA的呼吸效应分析了EGSM网络白天和晚上的外部干扰的差异,在此基础上,提出了通过使用背离边境的小区来承载话务,使用干净频点进行规划或使用1 800 MHz频段减弱外部干扰的方法,该方案在工程实测中取得了良好的效果。

The major factor affecting the EGSM network performance is the same frequency external interference from CDMA of other country in the border areas. A case which EGSM operator subject to a wide range of strong external interference by same frequency of neighbor country CDMA operators was analyzed, then a solution to reduce this external interference was proposed. Firstly, with KPI statistical and DT test analyze, the external interference source was located, and the intensity and scope of the effects also was confirmed. Then, using the rural Hata propagation model theoretically, the impact and scope of CDMA interference was analyzed; combined with the respiratory effects of CDMA network, the differences between day and night EGSM external interference were analyzed. Final, the solution was proposed, which use deviate cell of border to carry traffic, use the clean frequency band to plan or use the 1 800 MHz frequency to carry the traffic. Those solution weakened external interference, the KPI and user effecting of EGSM network has achieved good results.