In a ..................., a mobile station always communicates with just one base station.
In a Hard hand off a mobile station always communicates with just one base station.
A hard handoff is a handoff technique used with cellular networks that requires the user's connection to be entirely broken with an existing base station before being switched to another base station. ... A hard handoff is also known as a hard handover or break-before-make handover.
The handover or handoff process is of major importance within any cellular telecommunications network. It is necessary to ensure it can be performed reliably and without disruption to any calls.
SOft Handover:- When mobile ( in Call0 switches to a new sector/cell which is on the same frequency then it is called a soft handover. If the "new" sector is also from the same BTS then it is called a softer handover. UMTS networks omplements all types (Hard/Soft/Softer) of handovers.
Different approaches are proposed and applied in order to achieve better handoff service. The principal parameters used to evaluate handoff techniques are: forced termination probability and call blocking probability. ... Handoff (or handover) process is transferring an active call from one cell to another.