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.

Mobile communication system with position detection to facilitate hard handoff

Abstract: A system for facilitating handoff adapted for use with a telecommunications network. The system includes position equipment for determining the location of a mobile transceiver within a region containing a first cell and a second cell. A comparison circuit compares the location with a predetermined handoff area within the region and provides a control signal in response thereto. A handoff initiation circuit initiates handoff of the mobile transceiver between the first cell and the second cell in response to the control signal. In a specific embodiment, the handoff is a hard handoff. The position equipment includes Global Positioning System (GPS) equipment including a mobile unit GPS receiver and signal interface. The comparison circuit includes a positional database that stores latitudinal and longitudinal information corresponding to the predetermined handoff area. The comparison circuit also includes a Code Division Multiple Access selector. The selector begins tracking the position of the mobile transceiver when it is within a predetermined range of the predetermined handoff area. In a specific embodiment, the handoff initiation circuit includes a base station controller. The position equipment includes a base station positional detection system and a mobile unit positional detection system for determining the location of the mobile transceiver. The position database has map information depicting the coverage area of the first and second cells and the predetermined handoff area. The selector runs software for comparing the location to the map information and providing the control signal when the location is within the predetermined handoff area. The base station includes and implements instructions for completing hard handoff in response to the control signal.

Techniques to reduce the IEEE 802.11b handoff time

Abstract: We analyze the link-layer handoff process in wireless LANs based on the IEEE 802.11b standard and suggests how to reduce its duration. Firstly, we divide the process into three phases: detection, search and execution. Our performance measurements indicate that the detection and search phases are the main contributors to the handoff time. We show that the link-layer detection time can be reduced to three consecutive lost frames. We also show that the search time can be reduced at least by 20% using active scanning with the two timers that control its duration set to 1 ms and 10.24 ms. Several simulations illustrate the achieved reduction in handoff time.

S-MIP: a seamless handoff architecture for mobile IP

Abstract: As the number of Mobile IP (MIP) [C. Perkins, (1996)] users grow, so will the demand for delay sensitive real-time applications, such as audio streaming, that require seamless handoff, namely, a packet lossless Quality-of-Service guarantee during a handoff. Two well-known approaches in reducing the MIP handoff latency have been proposed in the literature. One aims to reduce the (home) network registration time through a hierarchical management structure, while the other tries to minimize the lengthy address resolution delay by address pre-configuration through what is known as the fast-handoff mechanism. We present a novel seamless handoff architecture, S-MIP, that builds on top of the hierarchical approach [H. Soliman et al. (2002)] and the fast-handoff mechanism [G. Dommety et al. (2002)], in conjunction with a newly developed handoff algorithm based on pure software-based movement tracking techniques [Z.-G. Zhou et al. (2002)]. Using a combination of simulation and mathematical analysis, we argue that our architecture is capable of providing packet lossless handoff with latency similar to that of L2 handoff delay when using the 802.11 access technology. More importantly, S-MIP has a signaling overhead equal to that of the well-known 'integrated' hierarchical MIP with fast-handoff scheme [H. Soliman et al. (2002)], within the portion of the network that uses wireless links. In relation to our S-MIP architecture, we discuss issues regarding the construction of network architecture, movement tracking, registration, address resolution, handoff algorithm and data handling.

System and method for automatically configuring and integrating a radio base station into an existing wireless cellular communication network with full bi-directional roaming and handover capability

Abstract: A radio base station in a mobile communication network collects information about the network and exchanges data with a configuration device, the Internet System Manager (iSM). The iSM automatically configures and integrates the base station into the network by defining configuration parameter settings that allow fill interoperation of the base station with the network, with regards to roaming and handover in particular, without the need to add or modify parameter settings in other existing network elements. A very large number and high geographical density of such base stations is supported with full interoperation between them, allowing to overcome limitations of conventional mobile communication networks in this regard, by utilizing a certain combination of parameter settings and a new method to address the different base stations in the network.

Location determination and handover in mobile radio systems

Abstract: A handover initiation system for a cellular radio network comprises means for determining both the distance of a mobile user from a cell base station based on propagation delay techniques and means for measuring the signal strength to determine the path taken by the mobile user. In a busy area microcells are constituted by single streets. The propagation characteristics of adjoining streets in a larger macrocell can be distinguished from the propagation characteristics of the street constituting the microcell such that the handover initiation of a mobile user within one of the surrounding streets can be determined.