Performance of movement-based location update and one-step paging in wireless networks with sparsely underlaid microcells

We study the performance of movement-based location up-date with one-step paging in a macrocell/microcell overlaid network. The network covers a whole service area with macrocells and high traffic density areas with microcells. The location tracking scheme requires each mobile platform (MP) to count the number of macrocell boundary crossings from the last location update and use the number, compared with two thresholds, to determine which tier to report to. If it is greater than or equal to the lower threshold the MP is allowed to update location information but report only to a low-tier microcell. If it reaches the higher threshold the MP reports immediately to the overlaying macrocell and resets the counter. For the scheme combined with one-step paging, expected total tracking cost per call is analyzed based on the MP mobility modelled as a semi-Markov chain with uniform transitions between neighboring microcell areas and the presence of a microcell determined by a Bernoulli trial with probability p of success. Results, corroborated by simulations, show that the analysis yields accurate performance bounds for a wide rage of parameters. This allows us to study the effects of several critical factors on tracking costs.