Modeling and Analysis of an Energy-Efficient Mobility Management Scheme in IP-Based Wireless Networks†

An energy-efficient mobility management scheme in IP-based wireless networks is proposed to reduce the battery power consumption of mobile hosts (MHs). The proposed scheme manages seven MH states, including transmitting, receiving, attention/cell-connected, attention/paging area(PA)-connected, idle, off/attached, and detached states, to efficiently manage battery power, radio resources, and network load. We derive the stationary probabilities and steady state probabilities of the seven MH states for the proposed scheme in IP-based wireless networks in compact form. The effects of various input parameters on MH steady state probabilities and power consumption are investigated in the proposed scheme compared to the conventional scheme. Network costs such as cell updates, PA updates, binding-lifetime-based registrations, and paging messages are analyzed in the proposed and conventional schemes. The optimal values of PA size and registration interval are derived to minimize the network cost of the proposed scheme. The combined network and power costs are investigated for the proposed and conventional schemes. The results provide guidelines to select the proper system parameters in IP-based wireless networks

The Node Distribution of the Random Waypoint Mobility Model for Wireless Ad Hoc Networks

The random waypoint model is a commonly used mobility model in the simulation of ad hoc networks. It is known that the spatial distribution of nodes moving according to this model is in general non-uniform. However, an in-depth investigation and a closed-form expression of this distribution is still missing. This fact impairs the accuracy of the current simulation methodology of ad hoc networks and makes it impossible to relate simulation results to analytical results on the properties of adhoc networks. To overcome these problems, we present a detailed analytical study of the node distribution resulting from random waypoint mobility. More specifically, we consider a generalization of the model, in which the pause time of the mobile nodes is chosen arbitrarily in each waypoint and a fraction of nodes may remain static for the entire simulation time. We show that the structure of the resulting distribution is the weighted sum of three independent components: the static, pause, and mobility component. This division enables us to understand how the model\u27s parameters influence the distribution. By describing mobility as a stochastic process, we derive an exact equation of the asymptotically stationary distribution for movement on a line segment, and an accurate approximation for a square area. The good quality of this approximation is validated through simulations with various settings of the mobility parameters

Producer mobility support scheme for indirection-based mobility approach in named data networking

Named Data Networking (NDN) is a clean-slate future Internet architecture proposed to support content mobility by using hierarchical naming instead of IP addresses for routing. The hierarchical naming structure of NDN offers more benefits in supporting consumer mobility. However, the movements of producer inflict changes in routing name prefix hierarchy, which makes the entire network unaware of the new location of the producer. Thus, it causes some significant challenges, such as unnecessary Interest packet losses, high handoff latency, high signaling overhead cost, poor utilization of bandwidth, and path stretching. The aim of this research is to propose a Producer Mobility Support Scheme (PMSS) in order to minimize the handoff latency, signaling cost, improve data packets delivery via optimal path once a content producer relocated. The proposed PMSS model includes the formulated Mobility Weighted Function to incorporate movement behavior of the mobile producer. Also, Mobility Interest packet was designed to convey binding information and Broadcasting Strategy to facilitate handoff processes by updating the intermediate routers. Therefore, modeling and simulation methodologies were used in the design and performance evaluation of PMSS for rigorous investigation. The analytical result of PMSS scheme outperforms Optimal Producer Mobility for Larger-scale scheme with 50% lower handoff latency and signaling cost. Moreover, it minimizes 46% handoff signaling cost and improves 32% data path optimization as compared to the Kite scheme. The simulation results show that the proposed PMSS scheme minimizes 40% handoff latency, 28% packets delay, 28% unnecessary Interest packets loss, and improves 20% throughput. This study contributes to the development of the movement behavior model and mobility update packets. The findings have significant implication to support seamless mobility and the integration of NDN with other networks without additional mechanism

Cooperative control of relay based cellular networks

PhDThe increasing popularity of wireless communications and the higher data requirements of new types of service lead to higher demands on wireless networks. Relay based cellular networks have been seen as an effective way to meet users’ increased data rate requirements while still retaining the benefits of a cellular structure. However, maximizing the probability of providing service and spectrum efficiency are still major challenges for network operators and engineers because of the heterogeneous traffic demands, hard-to-predict user movements and complex traffic models. In a mobile network, load balancing is recognised as an efficient way to increase the utilization of limited frequency spectrum at reasonable costs. Cooperative control based on geographic load balancing is employed to provide flexibility for relay based cellular networks and to respond to changes in the environment. According to the potential capability of existing antenna systems, adaptive radio frequency domain control in the physical layer is explored to provide coverage at the right place at the right time. This thesis proposes several effective and efficient approaches to improve spectrum efficiency using network wide optimization to coordinate the coverage offered by different network components according to the antenna models and relay station capability. The approaches include tilting of antenna sectors, changing the power of omni-directional antennas, and changing the assignment of relay stations to different base stations. Experiments show that the proposed approaches offer significant improvements and robustness in heterogeneous traffic scenarios and when the propagation environment changes. The issue of predicting the consequence of cooperative decisions regarding antenna configurations when applied in a realistic environment is described, and a coverage prediction model is proposed. The consequences of applying changes to the antenna configuration on handovers are analysed in detail. The performance evaluations are based on a system level simulator in the context of Mobile WiMAX technology, but the concepts apply more generally