An improved inter-frequency handoff trigger in a wireless communication system
is disclosed. In an embodiment of the invention, a particular mobile station transmits
a pilot strength measurement message to the base station. The base station subsequently
determines the strongest border pilot and the strongest interior pilot. The base
station evaluates whether the border sector is stronger than the interior sector.
If the border sector is stronger than the interior sector, this would indicate
that the mobile station is out of the coverage area of the interior pilot. The
base station subsequently determines the transmitted pilot energy to total transmit
power of the pilot signal associated with the border pilot. The transmitted pilot
energy to total transmit power of the border pilot is then compared to an aggregate
value of a set of pilot energy signals received at the mobile station and if the
difference exceeds a threshold value, the handoff of the mobile station to the
border sector base station is initiated.
