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One of the challenging tasks in Personal Communication Services (PCS) is to efficiently maintain the location of PCS subscribers who move from one region to another (hereafter called mobile users). When a mobile user receives a call, the network has to quickly determine its current location. The existing location management scheme suffers from high signaling traffic in locating the mobile users. Two-level forwarding pointer scheme has been proposed from per-user forwarding pointer scheme to reduce the cost of signaling traffic. In this paper, we enhance the two-level forwarding pointer scheme. When a mobile user moves from its current Registered Area (RA), which is served by Mobile Switching Center (MSC), to another RA the local switch that acts as a parent of those two MSCs maintains this movement in its memory (hereafter called cache entry).A cache entry is used to locate rapidly the mobile user instead of querying the Home Location Register (HLR) and waiting for its reply. HLR is centralized in the network and far away from the mobile users so that the signaling traffic crossing it is expensive. Sometimes the cache entry may be failed to reach the mobile user then a two-level forwarding pointers will be created from the corresponding Visitor Location Register (VLR), attached to its MSC, through a correct path to locate the mobile user. Thus, there is a saving in cost of querying the underlying HLR. The analytical results indicate that such proposal efficiently reduces the signaling traffic cost for all values of Call to Mobility Ratio (CMR), this is especially considerable when CMR > 1, without any increase in the call setup delay.

The cellular principle is an effective way to guarantee efficient utilization of the offered radio band. Although PCS networks use the cellular principle, the next generation of PCS networks needs more improvements in location management to face the increased number of users. Both an Enhanced Profile- Based Strategy (EPBS) for small-scale roaming and a Caching Two-Level Forwarding Pointer (C2LFP) strategy for large-scale roaming have been proposed. This chapter introduces a model that unites the above two strategies. The idea behind this model is based on applying those two location management strategies and specifying the physical parameters of PCS networks from mobility management’s point of view so that the underlying solutions can be more cost effective for location management. An evolutionary method using a constraint Genetic Algorithm (GA) has been used to achieve network parameters optimization. For convenience, we selected the planning problem with an appropriate set of parameters to be treated both genetically and analytically. Thus one can easily verify accuracy and efficiency of the evolutionary solution that would be obtained from the genetic algorithm. For more realistic environments, GA could be used reliably to solve sophisticated problems that combine the small-scale and large-scale roaming parameters of PCS networks. A case study is presented to provide a deep explanation of the proposed integration approach.

Routing the sensed data is considered a main challenge in Wireless Sensor Networks (WSN) because the routing characteristics may vary depending on the network application and/or the network architecture. Since most sensor network applications work in clusters, hierarchical routing protocols have been developed to fit this network topology. This paper introduces the performance differentials for most common hierarchical routing protocols such as Low Energy Adaptive Clustering Hierarchy (LEACH) and Threshold sensitive Energy Efficient sensor Network protocol (TEEN). The design parameters of sensor networks are analyzed to present a classification and comparison of LEACH, TEEN routing protocols. The two protocols are analyzed using different mobility models using NS2 simulation tool. This comparison reveals the important features that need to be taken into consideration while designing and evaluating new routing protocols for sensor networks.

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