In this paper, the analytical modeling of a time-threshold based multi-guard bandwidth allocation scheme is presented using a two-dimensional markov chain. The main idea of the scheme is based on monitoring the elapsed real time of handoff calls and according to a time threshold (t(e)), a handoff call is either slightly-prioritized or fully-prioritized. A slightly-prioritized handoff call has higher priority than a new call and lower priority than a fully-prioritized handoff call. Also in this paper, the numerical results obtained from two dimensional markov chain analysis are compared with the numerical results which are obtained using one-dimensional markov chain analysis and simulation ones. The simulation and analytical results agree well. The performances of different bandwidth allocation schemes are measured using a crucial general performance metric Z. Z, which is a performance/cost ratio, is a function of the new call blocking probability, handoff call dropping probability and system utilization all together. The results indicate that our scheme outperforms other traditional schemes.