Enhanced distance-based location management of mobile communication systems using a cell coordinates approach

Abstract

In managing the locations of mobile users in mobile communication systems, the distance-based strategy has been proven to have better performance than other dynamic strategies, but is difficult to implement. In this paper, a simple approach is introduced to implement the distance-based strategy by using the cell coordinates in calculating the physical distance traveled. This approach has the advantages of being independent of the size, shape, and distribution of cells, as well as catering for the direction of movement in addition to the speed of each mobile terminal. An enhanced distance-based location management strategy is proposed to dynamically adjust the size and shape of location area for each individual mobile terminal according to the current speed and direction of movement. It can reduce the location management signaling traffic of the distance-based strategy by half when mobile terminals have predictable directions of movement. Three types of location updating schemes are discussed, namely, Circular Location Area, Optimal Location Area, and Elliptic Location Area. Paging schemes using searching techniques such as expanding distance search based on the last reported location and based on the predicted location, and expanding direction search are also explored to further reduce paging signal traffic by partitioning location areas into paging areas.

Zero Configuration Adaptive Paging (zCap)

“…Several alternative update schemes and paging strategies have been proposed. The updating schemes in [4] and [5] propose that networks trace two and three static cell sets (LA/RA) respectively while a completely different approach is taken in [6]- [10] where static cell sets are replaced by or combined with a maximum allowed distances Δ from the last reported location .…”

“…The goal of the present work is to optimise updating and paging in 4G systems with respect to system efficiency and management complexity. Comparing LTE to the earlier proposals, it is noted that the two or three cell sets discussed in [4] and [5] have become (up to) 16 cell sets through TAI lists while the distance based approach [6]- [10] has not been adopted at all. The use of UE specific information for paging as in [11]- [18], is not only complex to collect and maintain, but also comes with significant privacy issues.…”

Location Management in PCS Networks Using Base Areas (BAs) and 2 Level Paging (2LP) Schemes

“…Such process is done by comparing MT's registered LAI with current broadcast LAI, if the two IDs are different, LR takes place. On the other hand, to deliver a call to a MT, the network pages all the cells within the LA in parallel (Zhang, 2002;Ng & Chan, 2005). The Location Area Identifier (LAI) composed of three parameters as illustrated in Figure 2.…”