The act of transferring support of a mobile from one base station to another is termed handoff. Handoff occurs when a call has to be handed off from one cell to another as the user moves between cells. In atraditional "hard" handoff, the connection to the current cell is broken, and then the connection to the new cell is made. This is known as a "break-before-make" handoff. Since all cells in CDMA use the samefrequency, it is possible to make the connection to the new cell beforeleaving the current cell. This is known as a "make-before-break" or "soft" handoff.

Soft handoff requires less power, which reduces interference and increases capacity. The implementation of handoff is different between the narrow band and the CDMA standards.This is an effort to analyze a soft handoff strategy, taking into consideration the trade-offs between selecting system parameters and the performance benefits. We consider a scenario involving two basestations and a single mobile, where the changes in the pilot signal strength are tracked and a conditional decision is made allowing communication with only one base station. This results as an outcome of simple measurements, which determine the strongest signal and results in handover to the corresponding base station.

In a CDMA system the same frequency band is shared between all the cells. Thus there is well-defined efficient bandwidth utilization. Though there is frequency reuse the orthogonal nature of the waveforms serves to distinguish between the signals that occupy the same frequency band. A typical handoff scenariois taken into account wherein the need for a mobile to alter its frequency or rather to switch its carrier frequency is negated. The main idea of a soft handoff scheme is to ensure that there is connectivity with the old base station while the new base station has been assigned to take control over the communication link. This way at a given instant of time we have the mobile maintaining a constant communication link with at least one base station simultaneously ensuring a non-disrupted call activity. The algorithm may be designed in such a way as to ensure that as soon as the mobile is within the range of the new cell, the old base station releases the connection of the call.

In power controlled CDMA systems soft handoff is preferred overhard handoff strategies. This is more pronounced when the IS-95 standard is considered wherein the transmitter power is adjusted dynamically during the operation. Here the power control and soft handoff are used as means of interference-reduction, which is the primary concern of such an advanced communication system. The previous and the new wideband channels occupy the same frequency band in order to make an efficient use of bandwidth, which makes theuse of soft handoff very important. The primary aim is to maintain a continuous link with the strongest signal base station otherwise a positive power control feedback would result in system problems. Softhandoff ensures a continuous link to the base station from which the strongest signal is issued. Soft handoffs are used as means of interference-reduction, which is the primary concern of such an advanced communication system. The previous and the new wideband channels occupy the same frequency band in order to make an efficient use of bandwidth, which makes the use of soft handoff very important.