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Topic: Handoff


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3G

  
  Rerouting for Handoff in a Wireless ATM Network
Handoff is the procedure by which a user's radio link is transferred between radio ports in the network without an interruption of the user connection.
The handoff procedure is performed to ensure the integrity of a radio connection and to minimize interference to the users in the coverage area of neighboring cells [4, 8].
After the handoff is completed, the initial radio port migrates the user connection to an optimal route in the network provided that the portable stays within the coverage area of the new radio port for an extended period of time.
www.comsoc.org /pci/private/1996/oct/Akyol.html   (6114 words)

  
 Handoff - Wikipedia, the free encyclopedia
In cellular telecommunications, the term handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another.
In telecommunications there are two reasons why a handoff (handover) might be conducted: if the phone has moved out of range from one cell site (base station) and can get a better radio link from a stronger transmitter, or if one base station is full the connection can be transferred to another nearby base station.
The most basic form of handoff is that used in GSM and analog cellular networks, where a phone call in progress is redirected from one cell site and its transmit/receive frequency pair to another base station (or sector within the same cell) using a different frequency pair without interrupting the call.
en.wikipedia.org /wiki/Handoff   (450 words)

  
 CDG : Technology : Welcome to the World of CDMA
The concept of an abrupt handoff is fundamentally flawed in the sense that static signal strength measurements cannot foretell the future.
The handoff is not abrupt, but rather it is a prolonged call state during which there is communication via two or more base stations.
The handoff can be completed either by the mobile moving completely into the new cell, or by the mobile returning to the original serving cell.
www.cdg.org /technology/cdma_technology/a_ross/Handoff.asp   (1397 words)

  
 Multiple TCP connection handoff   (Site not responding. Last check: 2007-11-03)
The handoff protocol allows the front-end to transfer its end of an established client connection to a back-end node.
The advantage of this multiple handoff protocol is that it allows content-based request distribution at the granularity of individual requests in the presence of persistent connections.
The handoff approach requires the operating systems on front-end and back-end nodes to be customized with a vendor-specific loadable kernel module.
www.usenix.org /event/usenix99/full_papers/aron/aron_html/node10.html   (259 words)

  
 Handoff or handover mechanism in Mobile WiMAX
For implementing a mobile network, a handoff mechanism must be defined to maintain uninterrupted user communication session during his/her movement from one location to another.
When used for delivering data traffic (such as web browsing and e-mail), soft handoff will result in lower spectral efficiency because this type of traffic is bursty and does not require continues handover from one BS to another.
In hard handoff, a connection with a BS is ended first before a SS switches to another BS.
www.conniq.com /WiMAX/handoff.htm   (272 words)

  
 Handoff in Cellular Systems
Handoff is a process of transferring a mobile station (MS) from one base station (BS) or channel to another.
Handoff algorithms with a specific set of parameters cannot perform uniformly well in different communication system deployment scenarios since these scenarios are characterized by specific environments.
The probability of a successful handoff can be improved by queuing handoff requests at the cost of increased new call blocking probability and a decrease in the ratio of carried-to-admitted traffic since new calls are not assigned a channel until all the handoff requests in the queue are served.
www.comsoc.org /pci/private/1998/dec/Tripathi.html   (12043 words)

  
 Inter-System Handoff Management   (Site not responding. Last check: 2007-11-03)
The inter-system handoff signaling protocol focuses on the handoff signaling procedures.
To achieve intersystem handoff using boundary cells, a new set of signaling messages was developed that must be transferred between the boundary cell base stations in network 1 and network 2, and the network switches (SW1 and SW2).
The extra signaling time has a very large impact on the overall handoff time for pico-cell and micro-cell networks as well as MEO and GEO satellite networks, due to the high bit rates at the lower terrestrial tiers and the large propagation times of the satellite networks.
users.ece.gatech.edu /wenye/3G/isho.html   (441 words)

  
 antoine-mip4-lowlatency-handoff-triggers-00.txt   (Site not responding. Last check: 2007-11-03)
Handoff Command - It is a message sent by an entity in the network to instruct the MN to initiate a handoff.
The criterion initiating the handoff is not restricted to the signal noise ratio perceived at lower layers.
The policy based handoff decision may be taken locally on the MN or may be implemented on a different node in the network.
bgp.potaroo.net /ietf/idref/draft-antoine-mip4-lowlatency-handoff-triggers   (2580 words)

  
 Framework for Seamless Roaming, Handoff and QoS Mapping in Next Generation Wireless Networks
Handoff Delay – It is calculated from the time BTS initiates Handoff Request on behalf of the mobile the time BTS gets Handoff Complete from MS, before ti switches over to the frequencies of the new network and channel.
The handoff delay and the data redirection delay were calculated manually as well as through the simulation results for validation purposes.
For the validation, the actual simulation time at every event in the handoff and redirection process was taken and was compared to the manually estimated time according to the delays that were incorporated in the model.
www.it.rit.edu /~ns/cisco_web/index2.htm   (2423 words)

  
 TCP Connection Handoff   (Site not responding. Last check: 2007-11-03)
The handoff remains transparent to the client in that all packets from the connection handling node appear to be coming from the front-end.
The TCP multiple handoff mechanism discussed in Section 3.2 can be implemented by extending the above design in the following manner.
One of the main challenges in this design is to prevent the TCP pipeline from draining during the process of a handoff.
www.usenix.org /events/usenix99/full_papers/aron/aron_html/node20.html   (197 words)

  
 Radio-Electronics.Com :: Mobile Phone Handover or Handoff
Although all of these forms of handover or handoff enable the cellular phone to be connected to a different cell or different cell sector, they are performed in slightly different ways and are available under different conditions.
This is called soft handover or soft handoff, and it is defined as a handover where a new connection is established before the old one is released.
Handover and handoff are performed by all cellular telecommunications networks, and they are a core element of the whole concept of cellular telecommunications.
www.radio-electronics.com /info/cellulartelecomms/cellular_concepts/handover_handoff.php   (1312 words)

  
 Cellular Wireless Network Handoff Protocols - ContentMasterWorld   (Site not responding. Last check: 2007-11-03)
NCHO is a centralized handoff protocol, in which it is network that makes handoff decision based on measurements of the signal quality of mobile station (MS) at a number of based stations (BS).
Thus, this type of handoff is not suitable to a rapid changing environment and a high density of users due to the associated delay.
In the course of handoff, a new connection is established first between the MS and a new BS, while keeping the old connection between the MS and the old station.
www.contentmasterworld.com /?a=articles&p=366   (585 words)

  
 P-Handoff
The first instances of vertical handoff [8] were found in overlay networks, where different cellular architecture are mutually overlaid in the same area offering different type of coverage (from local high speed to wide area lower speed).
A standard handoff (horizontal) is simply migrating within the same cellular architecture, and a vertical handoff is moving from a cell in one cellular architecture to a cell in a different architecture (for example GSM and 802.11).
Doing handoff at the IP level (see section 3.2) is natural because IP is stateless, connectionless, and common for most links, and it mostly amounts to changing a few routes in routing tables.
www.hpl.hp.com /personal/Jean_Tourrilhes/Papers/P-Handoff.html   (4784 words)

  
 MercuryMD.com index
Handoff promotes a streamlined and accurate patient handoff process by enhancing the communication and collaboration among cross-covering physicians and care teams.
MData Handoff is specifically designed to address the patient handoff process through a team-based approach focused on communication and collaboration.
With MData Handoff each member of the care team is able to track and edit patients’ Dx, code status, allergies, problem lists, and to-do tasks with complete visibility into a patient’s meds, labs and reports.
www.mercurymd.com /en/Products/EnterpriseModules/MDataHandoff/index.htm   (351 words)

  
 [No title]
Call handoff is the process of moving one end of an active call without creating a new logical call.
HANDOFF is designed to proceed quickly at the end of conferencing, thus media mixing in the transferee is not required.
HANDOFF initiated INVITEs MUST include a "Handoff" header, which can be used by targets and proxies to screen inappropriate calls from handoffs.
www.ietf.org /proceedings/01mar/I-D/dean-handoff-00.txt   (2462 words)

  
 [No title]
Microsoft Corporation 26 October 2003 Handoff Extension to RADIUS This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026.
Of course, where handoffs occur across different providers and access media, it is unlikely that session continuity can be preserved, since the client will be likely to change its IP address.
Where used in concert with this specification, such an Access-Request indicates that a handoff request is being anticipated and that the RADIUS server should send back an Access-Accept to allow the prospective handoff to occur, or an Access-Reject to deny the prospective handoff.
www.drizzle.com /~aboba/IEEE/draft-irtf-aaaarch-handoff-04.txt   (6879 words)

  
 Framework for Seamless Roaming, Handoff and QoS Mapping in Next Generation Wireless Networks
The predictive handoff scheme used earlier was modified to suit the framework.
Whereas without the framework, the handoff effects manifest as reduced throughtput for data calls and lost information for voice calls, in the case of handoff with the framework, the reduction in data throughput is reduced and there is no information loss for voice calls.
However the handoff delays as analysed were primarily due the layer 2 handoff, with different SSIDs.
www.it.rit.edu /~ns/cisco_web/index3.htm   (1386 words)

  
 Vhandoff: Vertical Handoff Software
This is version 1.0-alpha of the Daedalus project's Vertical Handoff software, which provides networking extensions to support the use of multiple wireless network interfaces in a Wireless Overlay Network structure.
This system is described in more detail in the paper Vertical Handoffs in Wireless Overlay Networks, which will be appearing in an upcoming issue of ACM Mobile Networking (MONET).
If one wants low-latency handoff and multicast care-of addresses, one would have to extend mobile-ip to have heirarchical foreign agents and the extra types of mobile<-->foreign agent communications.
daedalus.cs.berkeley.edu /software/vhandoff   (1864 words)

  
 VRC - Virtual Radar Client for VATSIM Controllers
This will initiate a handoff to the receiving controller, who will be notified of the handoff request in some manner, depending on which radar program he/she is using and which radar mode he/she has selected.
In VRC handoff requests are indicated by a sound and either a flashing datablock or a colored datablock, or both.
If another controller initiates a handoff of an aircraft to you, you will see a notification (either a flashing datablock or colored datablock or both) and optionally hear a sound.
www.metacraft.com /VRC/docs/doc.php?page=handoffs   (523 words)

  
 Vertical handoff - Wikipedia, the free encyclopedia
This is different from a 'horizontal handoff' between different wireless access points that use the same technology in that a vertical handoff involves changing the data link layer technology used to access the network.
Vertical handoffs between WLAN and UMTS (CDMA2000) have attracted a great deal of attention in all the research areas of the 4G wireless network, due to the benefit of utilizing the higher bandwidth and lower cost of WLAN as well as better mobility support and larger coverage of UMTS.
In traditional handoffs, such as a handoff between cellular networks, the handoff decision is based mainly on RSS (Relative Signal Strength) in the border region of two cells, and may also be based on call drop rate, etc. for resource management reasons.
en.wikipedia.org /wiki/Vertical_handoff   (602 words)

  
 4X100 Relay Handoffs
When I was coaching, we would start working on handoffs the very first practice and didn’t stop until the season was over … For some reason, kids love relays and don’t mind practicing them since it’s less competitive and seemingly easier than individual time trials or conditioning drills.
The sketch below shows the basic configuration of the handoff area which is comprised of an acceleration zone and a handoff zone.
After each handoff, the runner returns to the start line for that station and waits for the baton to come back around the track..
moptl.tripod.com /4x100_relay_handoffs.htm   (1675 words)

  
 lineHandoff   (Site not responding. Last check: 2007-11-03)
If NULL, the handoff target is the highest priority application that has opened the line for owner privilege for the specified media mode.
Call handoff allows ownership of a call to be passed among applications.
This form of handoff succeeds if the call handle is handed off to the same file name as the application requesting the handoff.
msdn.microsoft.com /library/en-us/wcesdkr/html/wcesdkrlineHandoff.asp?frame=true   (924 words)

  
 Implementation Issue: TCP Handoff   (Site not responding. Last check: 2007-11-03)
However, this half-connection is transparent to the client, so the TCP ACK packets from the client (which are only meaningful to the second proxy) will continue flowing to the first proxy.
After the TCP handoff, the first proxy still needs to forward the TCP ACK packets from the client to the second proxy.
Obviously, this TCP handoff requires changes to proxy server software and to the TCP/IP stacks on both proxies.
www.cs.princeton.edu /~lmwang/pubps/wcw/node10.html   (387 words)

  
 What is handoff? - A Word Definition From the Webopedia Computer Dictionary
Handoffs occur when a cellular phone user passes out of the range that the cell can handle and into another cell’s range, and the signal is passed from one base station to the next.
The handoff is transparent to the user and typically will not result in a loss of service unless the user moves out of range of a cell’s base station.
The transition and the process required to make the transition are both referred to as the handoff.
www.webopedia.com /TERM/H/handoff.html   (166 words)

  
 What is handoff? - a definition from Whatis.com   (Site not responding. Last check: 2007-11-03)
- In a cellular telephone network, handoff is the transition for any given user of signal transmission from one base station to a geographically adjacent base station as the user moves around.
In a properly functioning network, handoff occurs smoothly, without gaps in communications and without confusion about which base station should be dealing with the subscriber.
Subscribers to a network need not do anything to make handoff take place, nor should they have to think about the process or about which base station is dealing with the signals at any given moment.
searchmobilecomputing.techtarget.com /sDefinition/0,,sid40_gci335123,00.html   (341 words)

  
 Handoff time measurement   (Site not responding. Last check: 2007-11-03)
Of course, the handoff time depends >>of the beacon period that in my case is the default, thus 100 ms.
I recommend to read this paper to have an experimental understanding of the MAC layer handoff in 802.11: http://www.it.kth.se/~aep/publications/measurements-kanter-maguire-escudero.pdf The results shows that the measured handoff time was 157 ms.
Anyway, note that handoff time can be reduced with passive scanning if a shorter beacon period is used.
lists.shmoo.com /pipermail/hostap/2002-November/000236.html   (370 words)

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