A pointer forwarding based local anchoring (POFLA) scheme for wireless networks

For a Personal Communication System (PCS) network to effectively deliver services to the mobile users, it must have an efficient way to keep track of mobile users. Location management fulfills this task through location registration and call delivery procedures. To reduce the signaling traffic, many schemes such as local anchoring, pointer forwarding, and two-level pointer forwarding schemes have been proposed in the past few years. In this paper, we present a novel location management scheme, pointer forwarding based local anchoring scheme, that intends to mitigate the signaling traffic while keeping the tracking delay in check. In this scheme, one visitor location register (VLR) traversed by a user is selected as the mobility agent (MA) for the user at a time, which forms another level of management in order to make some registration traffic localized. The idea is as follows: instead of always carrying out location update to the home location register (HLR), which would become the bottleneck otherwise, many location updates are accomplished by the mobility agent. Moreover, pointers can be set up between VLRs under the coverage of the same MA. When the distance between the MA and the current VLR exceeds a certain threshold, the current VLR will become the new MA, which also updates the HLR (where a user's location information is the identification of the reported MA). The numerical results show that this scheme can significantly reduce the network signaling traffic load without increasing much of the call setup delay.