Write about Power difference handoff

A better algorithm is based on the power difference (Δ) of a mobile signal received by two cell sites, home and handoff. Δ can be positive or negative. The handoff occurs depending on a preset value of Δ.

Δ = the mobile signal measured at the candidate handoff site

− the mobile signal measured at the home site

For example, the following cases can occur.

Δ> 3 dB request a handoff

1dB <Δ< 3 dB prepare a handoff

−3dB <Δ< 0 dB monitoring the signal strength

Δ< −3 dB no handoff

Those numbers can be changed to fit the switch processor capacity. This algorithm is not based on the received signal strength level, but on a relative (power difference) measurement. Therefore, when this algorithm is used, all the call handoffs for different vehicles can occur at the same general location in spite of different mobile antenna gains or heights.