Supporting remote sensing and control over ip networks

In IP network based remote sensing and control systems, the operator controls a slave manipulator with sensing capabilities located at a remote site. Control commands and sensory feedback are transmitted through computer networks. The control and sensing data involved in such systems differentiate themselves from other media types in that they require both reliable and smooth delivery. Reliable delivery requires that the transport service have TCP style semantics. By being smooth, the transport service should be able to deliver the control and sensing data with both the average latency and the standard deviation of the latency bounded and reduced. Traditional transport services have great difficulty meeting the latency requirements of delivering sensing and control data over the communication networks. Remote sensing and control systems could be deployed in distant geographical locations, or places where network infrastructures are not available. In the former case, the Internet is an ideal communication channel due to its availability. In infrastructureless environments, Mobile Ad-hoc Networks (MANETs) can be a good choice. However, the transport protocols in both the Internet and MANETs have difficulty meeting the needs of this type of applications. We proposed a Supermedia TRansport over Overlay Networks (STRON) framework to improve the QoS of teleoperation systems over wide area networks. A QoS management frame work is also proposed to support STRON based teleoperation systems. A Transport service for Remote Sensing and Control (TRSC) over Wireless Networks is designed for MANET based applications. The proposed approaches were verified using experiments, network simulators and theoretical models. The popularity of third-generation wireless communication, handheld devices and local area wireless technologies makes pervasive computing environment a good incubator for remote sensing and control applications. Supporting remote sensing and control applications in pervasive computing environments poses new challenges to the transport protocols. In this part of the research we proposed a collaborative approach to support remote sensing and control in heterogeneous environments. We explore the spatial diversity provided by dual-mode terminals that are equipped with both WLAN and cellular interfaces. Multiple terminals serve as proxies to provide better QoS for the targeted application. We built a dynamic mechanism to determine the appropriate number of proxies to use. The mechanism utilizes the MAC layer retransmission rate as an indicator of the contention level in the MANET. We also examine the organization structures of the networks that support remote sensing applications. In order to adapt to the changing environments and provide resilient QoS, it is often desirable that the sensor network reorganize itself. We explore the opportunities and challenges of deploying low cost hopping sensors and utilizing their mobility to ensure coverage and maintain energy efficiency within a sensing field. Hopping sensors are able to maintain mobility in harsh terrain but may lack the movement accuracy of those sensors that are powered by wheels. We focus on the problem of transporting a number of hopping sensors from multiple sources to a destination. Probabilistic methods are used to contain the movement inaccuracies along the hopping course. We also consider the impact of wind under an aerodynamic setting. Two transport schemes are designed to minimize the number of hops needed while considering other constraints, such as sustaining the capability of relocating sensors within the whole network. The performance of the two schemes are evaluated and compared through simulations.