Location management utilizing initial position for mobile networks

摘要

The present invention provides a method for updating a mobile terminal (MT) for a mobile communication network when the MT crosses a boundary of a first location-update (LA) area. The method comprises determining a second LA to be assigned to the MT for replacing the first LA. The second LA is characterized by a LA center and a LA size, both determined by optimizing them in a sense that a mean total location-management cost is minimized without restricting the LA center to be fixed at the initial position. The initial position is defined as the location where the MT performs a latest location update at the first LA before crossing the boundary. This invention also provides schemes of partitioning the second LA into sub-paging areas for use in paging the MT when a call arrives at the network, so as to minimize the paging cost while satisfying delay requirements.

主权项

1. A method for updating a location of a mobile terminal (MT) for a mobile communication network when the MT crosses a boundary of a first location-update area (LA) assigned to the MT, an initial position of the MT being regarded as a location where the MT performed a latest location update at the first LA before crossing the boundary, the method comprising:
determining, by one or more computer processors in the mobile communication network, a second LA to be assigned to the MT for replacing the first LA, the second LA being characterized by a LA center and a LA size, wherein the LA center and the LA size are determined by numerically optimizing the LA center and the LA size in a sense that a mean total location-management cost predicted for the LA center and the LA size is minimized without restricting the LA center to be fixed at the initial position; wherein the LA center is located at a distance xopt from the initial position in a preferred movement direction of the MT; wherein the LA size is determinable by a LA radius, denoted as Ropt; and wherein the optimizing of the LA center and the LA size comprises determining xopt and Ropt, the determining of xopt and Ropt comprising the steps of: (1) generating a plurality of candidate LA-radius values; (2) for an individual candidate LA-radius value, denoted as R, determining a corresponding distance xopt,R that minimizes the mean total location-management cost conditioned on R; (3) repeating the step (2) for all the candidate LA-radius values to thereby obtain plural tuples of (R, xopt,R, Ctotal|R,xopt,R) where Ctotal|R,xopt,R is a value of the mean total location-management cost computed for R and xopt,R; and (4) identifying an optimal candidate pair among the plural candidate pairs such that the optimal candidate pair has the lowest value of Ctotal|R,xopt,R among the plural candidate pairs, whereby the values of R and xopt,R of the optimal candidate pair are Ropt and xopt, respectively.