Dynamic multi-step paging scheme in PMIPv6-based wireless networks

Significant IP mobility mechanisms have been designed to minimize the handover overhead of mobile nodes. Although many efficient algorithms such as Mobile IP, HMIP and PMIP have been proposed, they did not attempt to upgrade their paging mechanisms that also heavily affect the power consumption of mobile nodes. Considering a good paging scheme is important because more than 95% of mobile nodes are moving in the idle state and change their states to active only for paging area updates. However, existing paging schemes assume the configuration of fixed paging areas and do not explore the dynamic nature of a paging area size depending on the states of mobile nodes. In this paper, we propose a novel dynamic IP paging scheme, where a paging area size is configured dynamically based on the speed and direction of a mobile node. The performance evaluation results demonstrate that the proposed IP paging scheme reduces the power consumption, compared to a fixed IP paging scheme.

A cost-effective approach to selective IP paging scheme using explicit multicast

Clustered PMIPv6 (CPMIPv6) was proposed to reduce the PMIPv6 signalling cost by dividing the domain into clusters each with a Head-MAG used to control the intra-cluster operations. However, existing mobility protocols perform registration process even for idle nodes, which leads to degrade the protocol performance due to unnecessary location updates. On the other hand, paging technique is widely used in cellular networks to reduce the signalling required for idle nodes registration. Although several paging schemes were proposed to enhance the PMIPv6 performance, they are either based on central entity or they incur high signalling cost due to multicasting. Inspired by CPMIPv6 architecture, this paper proposes a low cost paging scheme where each cluster is considered as a paging area and head-MAGs entities are utilised to perform the paging functions within the cluster. The analytical results show that the proposed scheme outperforms the existing paging schemes in terms of paging signalling cost.

This paper proposes to extend Mobile IP with adaptive individual paging. Paging reduces the signaling cost of Mobile IP making it more adapted to wireless cellular IP networks. By reducing the number of location updates to be sent per mobile host, paging also minimizes power consumption of the mobile devices. In the proposed extension, each mobile host computes dynamically its optimal location area size according to its traffic and mobility parameters. The optimal size is the size that provides the best paging versus location update cost tradeoff and, as a result, minimizes the signaling load in the network. We compare, by simulation, the performance of the proposed scheme with that of Mobile IP [11], a paging scheme that uses fixed size location areas and Hierarchical Mobile IP [5]. We show that our extension provides a significant gain compared to Mobile IP and the fixed size paging scheme and performs as well and sometimes better than Hierarchical Mobile IP. We also show that the integration of adaptive individual paging within Hierarchical Mobile IP outperforms all schemes.

The mobility-enabling protocol mobile IP supports location registration but not paging. However, current cellular networks use registration as well as paging procedures to minimize signaling cost. Accordingly, an extension to mobile IP using distributed individual paging, the so-called DIP-MIP protocol, is proposed for managing mobility in IP-based cellular networks. In DIP-MIP, each mobile host derives its own paging area size by optimizing a signaling cost function based on its individual mobility pattern. The cost function itself may use either of two mobility models - fluid flow and random walk and the performance of DIP-MIP is analyzed for both. The impact of various parameters on the DIP-MIP signaling cost and the optimal size of the paging area is studied as well.

IEEE802.11 networks are changing its primary role of extension of private LANs to become an access technology in competition or collaboration with current cellular networks. In addition, large-scale IEEE802.11 deployments are a reality that mesh networks can contribute to expand. But not only, networks are changing; their users are doing the same. More portable devices as WiFi enabled PDAs or phones will allow an increase of their number and mobility, but suffering from severe battery constraints. In addition, the interest in VoIP over WLAN will introduce the need of establishing sessions to WLAN users and not only from them. In order to support similar conditions, current cellular systems make use of a dormant mode with paging support which is inexistent in the IEEE802.11 networks. In this paper we propose the introduction of IP paging in IEEE802.11 networks in order to solve this problem. The aim of this paper is to demonstrate the usability of IP paging in order to reduce the mobility signaling cost. This is achieved through a new analytical approach that evaluates the following parameters: the call-to-mobility ratio (CMR), the size of the radio access network (RAN) and the size of the paging area. The solutions analyzed are the Hierarchical Mobile IPv6 (HMIPv6) protocol and a new extended version of this with IP paging support. The novelty of this latter version lies in its use of distance-based dynamic paging areas and its specific design for IEEE802.11 networks.

Mobility management is an important aspect in LEO systems. In terrestrial wireless networks, the movement of the user triggers location updating and determines the paging scheme, while in LEO satellite systems, location updating and paging is mainly based on the movement of satellites. Terrestrial location management techniques must be altered to fit LEO systems. The paper introduces a modified movement-based location update and paging scheme in LEO networks. We propose the meta-cell concept, which includes two spot-beams of one satellite. First, we present a location management scheme based on the architecture with a meta-cell location area. Then, an analytical model is applied to formulate the cost of location updating and location paging for the movement and meta-cell based dynamic location update scheme. The comparison of performance between the meta-cell architecture method and the conventional signal-spot-cell architecture method is provided to demonstrate the cost-effectiveness and robustness of the proposed scheme under various parameters. To reduce the impact of meta-cell architecture on location paging cost, we present a forced location update strategy which is used in the case that the meta-cell includes two spot-beams from different satellites.

In sequential paging (SP) schemes, the paging process is considered on a per user basis. When an incoming call reaches a mobile terminal (MT), the associated location area is divided into several paging areas (PAs) and PAs are paged one by one until the MT is found. Even though SP algorithms can reduce the paging cost compared to blanket paging (BP), they introduce extra and unnecessary delay, and are not efficient. We present a pipeline paging (PP) scheme in which multiple paging requests (PRs) can be served in a pipeline manner for different paging areas. We study the proposed scheme via extensive simulations in terms of discovery rate, total delay, and cost under different traffic loads. Our study shows that the PP scheme outperforms both the BP and SP schemes in terms of discover rate and total delay, while maintaining a cost similar to that of the SP scheme. The study also shows that when the paging delay constraint D is as large as 6, the PP scheme achieves almost 171% of the BP's discovery rate and 58% of the BP's cost, whereas the SP's discovery rate is far less than that of the BP scheme.

In this paper, we present a comparison of IP routing in mobile environments. We consider four protocols: mobile IP, mobile IP with paging support, mobile IP regional registration and mobile IP regional registration with paging support. The comparison is done by mathematical modeling and simulation. The comparative metric is signaling costs which are measured by a composition of registration and paging messages. The comparison considers several system parameters such as the number of base stations in the paging area, cell perimeter and mobile node velocity.

This paper considers several optimization problems of sequential paging with aggregation mechanism which has been shown to reduce significantly the paging cost of a wireless communication system. An important problem is to find the optimal aggregation factor subject to a constraint on the average paging delay. Another problem is, given a cost function that depends on both paging cost and paging delay, how to find the optimal aggregation factor to minimize that cost function. We have formulated and shown that these can be solved nicely due to the monotonicity and convexity of the average paging cost function and paging delay function. We demonstrate that the optimization problems of the aggregate factor and subnet clustering are not separable. This leads to joint optimization problems of aggregation factor and clustering that are investigated in this paper. The paper presents different algorithms to solve these joint optimization problems using the monotonicity in the aggregation factor and the number of clusters of the average paging cost and delay with the unconstrained optimal clustering and the structures of the constrained optimal clustering.

This paper discusses how a mobility model can be used jointly with a mobile activity trace and evolutionary computation to reduce the signaling load related to mobility management, an important and fundamental task in any public land mobile network. For this purpose, a mobility model is used to determine the most probable locations of each mobile subscriber, and this information, in turn, is used to assign paging areas. This paging strategy is evaluated by taking into account different probability thresholds and time-delay constraints, and in a multiobjective way. Thus, we study the whole objective space of the problem, ensure the results that are not dependent on the configuration of registration areas used in the analysis, and take into account the signaling traffic of both paging and location updates (in contrast to other published works, in which only the reduction in the paging load is considered). The feasibility of this paging scheme is evaluated by means of a performance analysis, in which it is compared with other paging schemes widely used in the recent literature. Results show that this paging strategy can reduce the blanket paging load by an average of $\sim 56.73$ %. Furthermore, the performance analysis also shows that using evolutionary computation jointly with a paging procedure based on a mobility model is a very useful strategy for managing mobility in a public land mobile network, because it allows the total signaling load obtained by blanket paging to be reduced by $\sim 67.03$ %.

Most paging schemes are considered on a per-user basis, i.e., when an incoming call arrives to a mobile terminal (MT), a paging request (PR) is put in a queue in mobile switching center, and PRs are served in a first-in first-out manner. In this paper, we propose a simplified pipeline probability paging (PPP) scheme, which handles PRs in a pipeline manner with a paging delay constraint under the condition of known knowledge on location probabilities of individual MTs. We then provide a performance evaluation and comparison for blanket paging scheme, sequential probability paging, and PPP in wireless networks. Both analytical models and extensive simulations are adopted to study these schemes.

Application of AI techniques for locating mobile terminals in mobile wireless cellular networks: A novel paging scheme

The paper proposes an integrated location management scheme, based on our previously proposed novel rule-based paging scheme (RBPS) for reducing the cost of terminal paging in a cellular wireless environment. We extend that scheme to propose a complete location management scheme. This requires application of RBPS together with a judicious movement based location update (LU) scheme. Numerical results show that the proposed integrated location management scheme, called RBPS*, not only attempts to resolve the issue of inherent tradeoff between the cost components, comprised of paging and LU cost, but also does reduce the total cost for location management compared to the other schemes. RBPS* significantly outperforms RBPS and the GSM-adopted blanket paging scheme along with movement based LU. When compared with the popular shortest distance first (SDF) scheme, results are again encouraging. The proposed scheme, RBPS*, is a generic one and can be deployed on-line. It has the potential for use in next generation wireless networks, irrespective of any standards.

Efficient paging techniques are needed to reduce the cost of location management in mobile networks. Currently, all the cells of a location area (LA) are paged at the same time to locate the mobile user (MU). Efforts have been made to reduce the overhead paging bandwidth cost by using multi-step paging methods. However, in the case of multi-step paging schemes, such as sequential paging and intelligent paging, additional paging delay is introduced. It is shown that if the paging cost computation is based on the number of paged cells only, then, in certain cases, one may obtain misleading results. To resolve this dilemma, a new cost function, in terms of the number of cells paged and the paging delay, is introduced. Thus, this new metric provides a powerful tool that can be used to analyze all multi-step paging procedures with constrained or unconstrained delay.