The design of the seamless handoff is the key issue in the next‐generation mobile networks. A new broadband wireless access, called WiMAX, has been specified in the IEEE 802.16e standard document, to provide the high bandwidth and the large coverage area than the IEEE 802.11‐based wireless networks. In the IP‐based mobile network, mobile IPv6 (MIPv6) protocol provides the binding update message to update the mobile station's IP information for supporting the layer 3 mobility. Hierarchical mobile IPv6 (HMIPv6) protocol is proposed by employing a hierarchical network structure to reduce handoff latency. HMIPv6 protocol suffers the long handoff delay and the high packet lost in the macro mobility. This paper presents a new cross‐layer partner‐assisted handoff mechanism based on HMIPv6, termed as P_HMIPv6 protocol. The P_HMIPv6 protocol is a cross‐layer approach by the combination of layer 2 and layer 3. The partner station (PS) is a new component with relay ability and adopted by our protocol. With the assistance of the PS, care‐of address (CoA) is pre‐acquired and DAD operation is pre‐executed by the PS before the MS initiates the layer 2 handoff. The simulation results show that P_HMIPv6 protocol actually achieves the performance improvements in handoff delay time, packet loss rate, and handoff delay jitter. Copyright © 2009 John Wiley & Sons, Ltd.

In this paper 1 , a new approach is proposed to reduce handoff operation in IEEE 802.16e network. Traditional mobile approaches, such as mobile IPv6 (MIPv6) and hierarchical MIPv6 (HMIPv6), can support smoothly handoff. These approach, ,unfortunately, suffer large handoff delay and packet lost in macro mobility for mobile users. With the aid of the partner node, DAD operation can be pre-executed by the partner node before the mobile node initialize the handoff request. we propose a cross-layer partner based fast handoff mechanism based on HMIPv6 in IEEE 802.16e network, called as P −HMIPv6 protocol. The P −HMIPv6 protocol is a cross-layer, layer 2 and layer 3, approach. The partner station (PS), which is a new component with relay ability and adopted by our protocol, is a static mobile station (MS). With the aid of the PSs, care-of address (CoA) can be pre-acquired and DAD operation can be pre-executed by the PS before the MS initials the layer 2 handoff. The simulation results show that P −HMIPv6 protocol actually achieves the performance improvements in the handoff delay time and the packet loss.

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-This paper describes the design of an indoor surveillance system capable of wall following and human detection based on intelligent mobile robot navigation. The wall following is performed based on a differential velocity control using type-2 fuzzy logic for a wheeled mobile robot equipped with IR sensors and sonar sensors, and human detection is performed by a human detection sensor. We have tested the application of our design in mobile robot for an indoor surveillance task of a polygon terrain using right wall following. The surveillance system of mobile robot is effective to work well in our testing.

Current deterministic sensor deploying methods always include the uncovered space greedily to reduce the number of deployed sensors. Because the sensing area of each sensor is circle-like, these greedily methods often divide the region of interest to multiple tiny and scattered regions. Therefore, many additional sensors are deployed to cover these scattered regions. This paper proposes a Jigsaw-based sensor placement (JSP) algorithm for deploying sensors deterministically. Sensors are placed at the periphery of the region of interest to prevent separating the region of interest to isolated regions. An enhanced mechanism is also proposed to improve the time complexity of the proposed method. The scenarios with and without obstacles are evaluated. The simulation results show that the proposed method can cover the whole region of interest with fewer deployed sensors. The effective coverage ratio of JSP method is less than 2. It is better than the maximum coverage method and the Delaunay triangulation method. The deploying sensors have more efficient coverage area, and the distribution of the incremental covered area is close to normal distribution.