Mobility is the most important feature of a wireless cellular communication system. This continuous service is achieved by handoff (or handover) from one cell to another cell. Handoff (also called handover) is the mechanism that transfers an ongoing call from one cell to another cell as a user moves through the coverage area of a wireless cellular system. The main objective of handover is to maintain the ongoing calls. Many times it is initiated by crossing a cell boundary or by deterioration in quality of the signal in the current channel.