Periodic Route Optimization for Handed-off Connections in Wireless ATM Networks

In Wireless ATM networks, user connections need to be rerouted during handoff as mobile users move among base stations. The rerouting of connections must be done quickly with minimal disruption to traffic. In addition, the resulting routes must be optimal. A reasonable approach is to implement handoff in two phases. In the first phase connections are rapidly rerouted and in the second phase a periodic route optimization procedure is executed. The route optimization should impose minimal signaling and processing load on the ATM switches. In this paper, we propose and study a periodic execution of route optimization for a two-phase handoff scheme. We study two types of execution: non-adaptive and adaptive. For the adaptive optimization, we consider two adaptation schemes that are dependent on network conditions. A simulation model is developed to study system performance. The adaptive route optimization is shown to minimize signaling and processing load while maximizing utilization of reserved resources

Periodic Route Optimization for Handed-off Connections in Wireless ATM Networks

In Wireless ATM networks, user connections need to be rerouted during handoff as mobile users move among base stations. The rerouting of connections must be done quickly with minimal disruption to traffic. In addition, the resulting routes must be optimal. A reasonable approach is to implement handoff in two phases. In the first phase connections are rapidly rerouted and in the second phase a periodic route optimization procedure is executed. The route optimization should impose minimal signaling and processing load on the ATM switches. In this paper, we propose and study a periodic execution of route optimization for a two-phase handoff scheme. We study two types of execution: non-adaptive and adaptive. For the adaptive optimization, we consider two adaptation schemes that are dependent on network conditions. A simulation model is developed to study system performance. The adaptive route optimization is shown to minimize signaling and processing load while maximizing utilization of reserved resources

Periodic Route Optimization for Handed-off Connections in Wireless ATM Networks

In Wireless ATM networks, user connections need to be rerouted during handoff as mobile users move among base stations. The rerouting of connections must be done quickly with minimal disruption to traffic. In addition, the resulting routes must be optimal. A reasonable approach is to implement handoff in two phases. In the first phase connections are rapidly rerouted and in the second phase a periodic route optimization procedure is executed. The route optimization should impose minimal signaling and processing load on the ATM switches. In this paper, we propose and study a periodic execution of route optimization for a two-phase handoff scheme. We study two types of execution: non-adaptive and adaptive. For the adaptive optimization, we consider two adaptation schemes that are dependent on network conditions. A simulation model is developed to study system performance. The adaptive route optimization is shown to minimize signaling and processing load while maximizing utilization of reserved resources

A Two-Phase Handoff Scheme for Mobility Management in Wireless ATM Networks

Mobility management in Wireless ATM networks poses a number of technical issues. An important issue is the ability to manage and reroute on-going connections during handoff as mobile users move among base stations. We propose a two- phase handoff management scheme using permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). The virtual paths are used in the first phase to rapidly reroute user connections. In the second phase, a distributed optimization process is initiated to optimally reroute handed-off connections. The paper also describes an adaptive optimization scheme to achieve high reserved bandwidth utilization. We analytically calculate and study the bandwidth requirement for the reserved virtual paths and handoff blocking probability. We also study the impact of processing and signaling load due to the second-phase route optimization. Both ATM CBR and VBR traffic types were considered for mobile users

A Two-Phase Handoff Scheme for Mobility Management in Wireless ATM Networks

Mobility management in Wireless ATM networks poses a number of technical issues. An important issue is the ability to manage and reroute on-going connections during handoff as mobile users move among base stations. We propose a two- phase handoff management scheme using permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). The virtual paths are used in the first phase to rapidly reroute user connections. In the second phase, a distributed optimization process is initiated to optimally reroute handed-off connections. The paper also describes an adaptive optimization scheme to achieve high reserved bandwidth utilization. We analytically calculate and study the bandwidth requirement for the reserved virtual paths and handoff blocking probability. We also study the impact of processing and signaling load due to the second-phase route optimization. Both ATM CBR and VBR traffic types were considered for mobile users

A Two-Phase Handoff Scheme for Mobility Management in Wireless ATM Networks

Mobility management in Wireless ATM networks poses a number of technical issues. An important issue is the ability to manage and reroute on-going connections during handoff as mobile users move among base stations. We propose a two- phase handoff management scheme using permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). The virtual paths are used in the first phase to rapidly reroute user connections. In the second phase, a distributed optimization process is initiated to optimally reroute handed-off connections. The paper also describes an adaptive optimization scheme to achieve high reserved bandwidth utilization. We analytically calculate and study the bandwidth requirement for the reserved virtual paths and handoff blocking probability. We also study the impact of processing and signaling load due to the second-phase route optimization. Both ATM CBR and VBR traffic types were considered for mobile users

Exploring the use of mobile sensors for noise and black carbon measurements in an urban environment

Mobile measurements have been collected on a bicycle equipped with a global positioning system (GPS) in a few connecting streets in Gent (Belgium). The 1-s sound pressure levels and 1-s black carbon concentrations were measured. In addition, 5 continuous monitoring fixed stations connected to building facades were used. Different processing methods are compared, based on different temporal and spatial weighting aggregations. The possibility to take profit of the fixed stations to refine estimations is tested, according to the noise levels collected at fixed stations and the distance between mobile and fixed sensors. In a last step, route selection based on travel distance, noise levels and black-carbon measurements is explored based on the data obtained

Advancing the Standards for Unmanned Air System Communications, Navigation and Surveillance

Under NASA program NNA16BD84C, new architectures were identified and developed for supporting reliable and secure Communications, Navigation and Surveillance (CNS) needs for Unmanned Air Systems (UAS) operating in both controlled and uncontrolled airspace. An analysis of architectures for the two categories of airspace and an implementation technology readiness analysis were performed. These studies produced NASA reports that have been made available in the public domain and have been briefed in previous conferences. We now consider how the products of the study are influencing emerging directions in the aviation standards communities. The International Civil Aviation Organization (ICAO) Communications Panel (CP), Working Group I (WG-I) is currently developing a communications network architecture known as the Aeronautical Telecommunications Network with Internet Protocol Services (ATN/IPS). The target use case for this service is secure and reliable Air Traffic Management (ATM) for manned aircraft operating in controlled airspace. However, the work is more and more also considering the emerging class of airspace users known as Remotely Piloted Aircraft Systems (RPAS), which refers to certain UAS classes. In addition, two Special Committees (SCs) in the Radio Technical Commission for Aeronautics (RTCA) are developing Minimum Aviation System Performance Standards (MASPS) and Minimum Operational Performance Standards (MOPS) for UAS. RTCA SC-223 is investigating an Internet Protocol Suite (IPS) and AeroMACS aviation data link for interoperable (INTEROP) UAS communications. Meanwhile, RTCA SC-228 is working to develop Detect And Avoid (DAA) equipment and a Command and Control (C2) Data Link MOPS establishing LBand and C-Band solutions. These RTCA Special Committees along with ICAO CP WG/I are therefore overlapping in terms of the Communication, Navigation and Surveillance (CNS) alternatives they are seeking to provide for an integrated manned- and unmanned air traffic management service as well as remote pilot command and control. This paper presents UAS CNS architecture concepts developed under the NASA program that apply to all three of the aforementioned committees. It discusses the similarities and differences in the problem spaces under consideration in each committee, and considers the application of a common set of CNS alternatives that can be widely applied. As the works of these committees progress, it is clear that the overlap will need to be addressed to ensure a consistent and safe framework for worldwide aviation. In this study, we discuss similarities and differences in the various operational models and show how the CNS architectures developed under the NASA program apply

A Novel Handoff Scheme for Wireless ATM Networks

Mobility support and management in Wireless ATM networks poses a number of technical issues. An important issue is the ability to manage and reroute active connections during handoff as mobile users move among base stations. We propose a novel two-phase handoff scheme using permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). The virtual paths are used in the first phase to rapidly reroute user connections. In the second phase, a distributed optimization process is initiated to optimally reroute handed-off connections. In this paper, we address various control issues related to signaling and implementation of such a scheme including how to achieve optimal paths. We analytically calculate and study the handoff blocking probability and the bandwidth requirement for the reserved virtual paths. We also study the impact of processing and signaling load due to the second-phase route optimization. Both ATM CBR and VBR traffic types were considered for mobile user connections