Discrete-time level-crossing analysis of soft handoff performance in cellular networks

In this correspondence, we develop a formal method for solving a class of level-crossing problems in discrete-time with application to the analysis of soft handoff performance in cellular networks such as code-division multiple-access (CDMA) systems. In such networks, proper dimensioning of soft handoff parameters is critical to overcoming propagation impairments and providing a transparent radio access service for multiple user profiles. We obtain exact expressions for the cell assignment and active set update probabilities of a mobile station traveling along an arbitrary straight-line trajectory. We develop recursive algorithms to compute performance measures such as outage probability, macrodiversity gain, and signaling load. The discrete-time level-crossing analysis yields an accurate and efficient computational tool for designing and dimensioning high performance soft handoff algorithms while avoiding the need for approximations or time-consuming computer simulations.