On the Influences of Enlarging or Shrinking the Soft Handoff Coverage for a Cellular CDMA System
Tsang‐Ling Sheu, Jaw-Huei Hou · 2007
This paper is concerned with the influences of enlarging or shrinking the soft hand-off coverage on the new-call blocking and the handoff-call dropping probabilities in a cellular CDMA system. In the proposed analytic model, we assume a cell is in hexagonal shape with two parameters, a and b, representing the soft handoff region between the outer and the inner cell. In the traffic model, we assume mobile stations are uniformly distributed over the service area and the new-call generation rate per unit area is a Pois-son process. Enlarging the soft handoff region may significantly increase the blocking and the dropping probabilities, while shrinking the soft handoff region can reduce the two probabilities slightly. The effect of activating a call admission control is also dis-cussed. As new-call generation rate per unit area is small, reserving 40 % of code chan-nels for handoff calls can reduce the handoff-call dropping probability from 10-4 to 10-8, while the new-call blocking probability is increased form 10-3 to 10-1. Finally, the ana-lytical model is compared with a previous work and a simulation is performed to validate the accuracy of our proposed model.