Modeling and analysis of queuing handoff calls in single and two-tier cellular networks

Two-tier cellular networks consist of a group of contiguous microcells overlaid by a macrocell. This design provides an enhanced use of the networks’ resources for both high and low speed users because of the availability of additional channels. However, this causes an increase in the number of handoffs between cells due to having smaller cell sizes in the microcell tier. Since, handoff call blocking is less desirable than new call blocking, delaying the handoff calls using a queue is an effective approach used to prevent the dropping of ongoing calls in a cellular network. Several techniques have been previously proposed to solve this problem. In this study, we extended the analysis of a previously proposed model by taking into account the effect of having different queue times for each type of users in the cellular network. We proposed new Markov models for single and two-tier cellular networks to solve the handoff call dropping problem. The paper presents solutions, performance analysis and comparisons of the proposed models with previously done work. As a result, it is shown that the proposed two-tier models have superior performance.