Patent ID: 6487416
Filing Date: 2002-11-26
Classification: H01Q,H04W

Abstract:
A method for controlling downtilt of an antenna in a sector of a cell of a code division multiple access (CDMA) network for mobile devices, the method comprising:monitoring current network conditions; estimating relative external interference rejection at a plurality of antenna downtilts for the current network conditions according to: IR(&PSgr;)=1/(1+&eegr;(&PSgr;)) â€ƒwherein &PSgr; is the downtilt angle, IR(&PSgr;) is the estimated relative external interference rejection at downtilt angle &PSgr;, and &eegr;(&PSgr;) is a loading factor at downtilt angle &PSgr;, the loading factor being determined according to: &eegr;(&PSgr;)=Iext (&PSgr;)/Iin(&PSgr;) â€ƒwherein Iext (&PSgr;) is out-of-cell interference at downtilt angle &PSgr;, and Iin(&PSgr;) is same-sector interference at downtilt angle &PSgr;; estimating relative sectorization efficiency at the plurality of antenna downtilts for the current network conditions according to: Esec(&PSgr;)=(Iin(&PSgr;)+Iext(&PSgr;))/(Iin(&PSgr;)+Isec(&PSgr;)+Iext(&PSgr;)) â€ƒwherein Esec (&PSgr;) is the estimated relative sectorization efficiency at downtilt angle &PSgr; and wherein Isec (&PSgr;) is the inter-sector interference at downtilt angle &PSgr;; estimating relative sector capacity at the plurality of antenna downtilts for the current network conditions based on a product of the corresponding relative external interference rejection and the corresponding relative sectorization efficiency; selecting the antenna downtilt based on the relative sector capacity at the plurality of antenna downtilts; and dynamically applying the selected downtilt to the antenna.