Handover

About: Handover is a research topic. Over the lifetime, 24219 publications have been published within this topic receiving 296416 citations. The topic is also known as: handoff.

Exploring mobile/WiFi handover with multipath TCP

Abstract: Mobile Operators see an unending growth of data traffic generated by their customers on their mobile data networks. As the operators start to have a hard time carrying all this traffic over 3G or 4G networks, offloading to WiFi is being considered. Multipath TCP (MPTCP) is an evolution of TCP that allows the simultaneous use of multiple interfaces for a single connection while still presenting a standard TCP socket API to the application. The protocol specification of Multipath TCP has foreseen the different building blocks to allow transparent handover from WiFi to 3G back and forth. In this paper we experimentally prove the feasibility of using MPTCP for mobile/WiFi handover in the current Internet. Our experiments run over real WiFi/3G networks and use our Linux kernel implementation of MPTCP that we enhanced to better support handover. We analyze MPTCP's energy consumption and handover performance in various operational modes. We find that MPTCP enables smooth handovers offering reasonable performance even for very demanding applications such as VoIP. Finally, our experiments showed that lost MPTCP control signals can adversely affect handover performance; we implement and test a simple but effective solution to this issue.

Toward seamless human-robot handovers

Abstract: A handover is a complex collaboration, where actors coordinate in time and space to transfer control of an object. This coordination comprises two processes: the physical process of moving to get close enough to transfer the object, and the cognitive process of exchanging information to guide the transfer. Despite this complexity, we humans are capable of performing handovers seamlessly in a wide variety of situations, even when unexpected. This suggests a common procedure that guides all handover interactions. Our goal is to codify that procedure.To that end, we first study how people hand over objects to each other in order to understand their coordination process and the signals and cues that they use and observe with their partners. Based on these studies, we propose a coordination structure for human-robot handovers that considers the physical and social-cognitive aspects of the interaction separately. This handover structure describes how people approach, reach out their hands, and transfer objects while simultaneously coordinating the what, when, and where of handovers: to agree that the handover will happen (and with what object), to establish the timing of the handover, and to decide the configuration at which the handover will occur. We experimentally evaluate human-robot handover behaviors that exploit this structure and offer design implications for seamless human-robot handover interactions.

Optimizations for vertical handoff decision algorithms

Abstract: Future wireless networks must be able to coordinate services within a diverse network environment. One of the most challenging problems for coordination is vertical handoff, which is the decision for a mobile node to handoff between different types of networks. While traditional handoff is based on received signal strength comparisons, vertical handoff must evaluate additional factors, such as, monetary cost, offered services, network conditions, and user preferences. In this paper, several optimizations are proposed for the execution of vertical handoff decision algorithms, with the goal of maximizing the quality of service experienced by each user. First, the concept of policy-based handoffs is discussed. Then, a cost function is defined to judge target networks based on a variety of user- and network-valued metrics. Finally, a performance analysis demonstrates that significant gains in quality of service and a more efficient use of resources can he achieved from the proposed optimizations.

Method and apparatus for short handover latency in wireless communication system using beam forming

Abstract: Beam selection is provided. A method for handover in a mobile station includes sending a scan request message for scanning a downlink (DL) beam with respect to a serving base station (BS) and a neighboring BS, to the serving BS, and receiving a scan response message; determining the DL beam for the MS by performing scanning with the serving BS and the neighboring BS based on the scan response message; sending a scan report message comprising a result of the scanning to the serving BS; when receiving an air-HO request message from the serving BS, generating an air-HO response message comprising information of a neighboring BS to which the MS hands over based on the air-HO request message; performing beam selection with the neighboring BS of the handover based on the air-HO request message; and performing the handover.

Proactive key distribution using neighbor graphs

Abstract: User mobility in wireless data networks is increasing because of technological advances, and the desire for voice and multimedia applications. These applications, however, require that handoffs between base stations (or access points) be fast to maintain the quality of the connections. In this article we introduce a novel data structure, the neighbor graph, that dynamically captures the mobility topology of a wireless network. We show how neighbor graphs can be utilized to obtain a 99 percent reduction in the authentication time of an IEEE 802.11 handoff (full EAP-TLS) by proactively distributing necessary key material one hop ahead of the mobile user. We also present a reactive method for fast authentication that requires only firmware changes to access points and hence can easily be deployed on existing wireless networks.