Cell of Origin (COO) is a method for locating mobile devices in GSM networks and in WLANs. In mobile networks, the COO method uses the cellID; in WLANs, it works with the name or IP address of the access point( AP).
The COO method is a relatively simple method in which the radio cell in which the mobile device is currently located is determined via the visitor location register( VLR). The location accuracy is relatively limited and depends solely on the radio cell size. It can be ten kilometers or more. For WLANs, the location accuracy is between 20 m and 50 m indoors and around 200 m outdoors.
To improve location accuracy, the radio cells are divided into three sectors using Cell Sectors( CS). The division is done with directional antennas that cover only a certain area of the radio cell. The location accuracy of the COO method is not very high. However, the method has the advantage that it can determine the position of the subscriber very quickly. The positioning accuracy can be increased by combining it with other signals and information such as timing advance( TA) or network measurement report( NMR).