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MINIMIZATION OF HANDOFF FAILURE PROBABILITY IN NGWS USING CHMP
Abstract
Next-generation wireless systems (NGWS) integrate different wireless networks, each of which is optimized for some specific services and coverage area to provide ubiquitous communications to the mobile users. In this paper, we propose to enhance the handoff performance of mobile IP in wireless IP networks by reducing the false handoff probability in the NGWS handoff management protocol. The handoff performance of Mobile IP is analyzed with respect to its sensitivity to the page link layer (Layer 2) and network layer (Layer 3) parameters Then, a Cross-layer Handoff Management (CHMP) architecture is developed using the insights learnt from the analysis. Based on this architecture, the detailed design of CHMP is carried out. Finally, extensive simulation experiments are carried out to evaluate the performance of CHMP. The theoretical analysis and simulation results show that CHMP significantly enhances the performance of both intra and intersystem handoffs .Based on the information of false handoff probability analyze its effect on mobile speed and handoff signaling delay.
Keywords- Next-generation wireless systems, Handoff management, cross-layer protocol design, and ubiquitous communications.
I. INTRODUCTION
Rapid progress in the research and development of wireless networking and communication technologies has created different types of wireless communication systems, such as Bluetooth for personal area, IEEE 802.11-based WLANs for local area, Universal Mobile Telecommunications System (UMTS) for wide area, and satellite networks for global networking. These networks are complementary to each other and, hence, their integration can realize unified next-generation wireless systems (NGWS) that have the best features of the individual networks to provide ubiquitous “always best connection”[10] to the mobile users .In the integrated NGWS, users are always connected to the best available networks and switch between different networks based on their service needs . It is an important and challenging issue to support seamless mobility management in the NGWS. Mobility management contains two components: location management and handoff management Location management enables the system to track the locations of mobile users between consecutive communications. On the other hand, handoff management is the process by which users keep their connections active when they move from one base station (BS) to another. There exist efficient location management techniques in the literature for NGWS However; seamless support of handoff management in NGWS is still an open research issue.
A cell is the radio area covered by a transmitting station or a Base Station (BS). All Mobile Terminals (MTs) within that area are connected and serviced by the BS. Therefore, ideally, the area covered by a cell is a circle, with the BS being at the centre. Thus, actually cells are not hexagonal. Hexagon fitted the planed area nicely and hexagon is the greatest area in the circle with respect to any other shape. The cell is therefore approximated to a regular hexagon and side of the hexagon is the common cord of two adjacent cells. When any MT crosses a common cord of a cell, we can say that handoff has occurred from one cell to another cell we consider a seven cell cluster in Fig.1. ABCDEF is a regular hexagon. Here, these adjacent seven are fitted in such a manner that no vacant places are left between them and the common cord between two circular cells are the side of the hexagon.. As the hexagon fitted the planed area nicely so we can imagine that the shape o f the cell is a regular hexagon and it is the maximum area in the circular cell (shaded area) with respect to any other shape The coverage areas are irregular because the radiation pattern of the base station antennas, buildings, trees, mountains, and other terrain features. Adjacent coverage areas may overlap considerably. Some overlap is desired because handoff is required in mobile communications systems when an MS moves from one BS coverage area to another during the course of a conversation