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 for accomplishing handover with phase difference of frame sync signals corrected

Abstract: A method of switching a communication channel when a mobile station moves from one service area to another service area is disclosed. The mobile station determines a difference between the transmission phase of a frame synchronizing signal received from a first base station currently holding a communication channel with the mobile station and the transmission phase of a frame synchronizing signal received from a second base station expected to newly set up a communication channel with the mobile station. The mobile station sends phase difference information representative of the above difference to the first base station via the communication channel. The first base station having received the phase difference information transfers the information to the second base station, causing it to correct the phase of data thereof to be sent to the mobile station. This successfully implements soft handover while guaranteeing the phase synchronization of frames sent from the two base stations.

Handover messaging in an unlicensed mobile access telecommunications system

Abstract: Methods and messages for performing handovers between an unlicensed mobile access network (UMAN) comprising a first radio access network and a second radio access network. URR (UMA radio resource) handover messages are exchanged between a mobile station (MS) and a UMA network controller (UNC) operating in the UMAN. The MS may access the UMAN via a wireless access point (AP) that is communicatively coupled to the UNC via an IP network. The URR handover messages are sent between the MS and the UNC using an Up interface comprising a set of layered protocols over an underlying IP transport. The handover methods include both handover from a UMAN to the second radio access network, and handover from the second radio access network to the UMAN.

Spectrum Handoff for Cognitive Radio Networks: Reactive-Sensing or Proactive-Sensins?

Abstract: In this paper, we will investigate the spectrum handoff schemes for the cognitive radio networks. Spectrum handoff occurs when the primary users appear and the secondary users are using this particular primary user's licensed channel. We compare two major types of spectrum handoff schemes. One is the reactive-sensing spectrum handoff, where the target channel for spectrum handoff is selected or sensed only after the spectrum handoff request is made. The other one is the proactive-sensing spectrum handoff, for which the target channel is predetermined. The advantage of the reactive spectrum handoff is the accuracy of the selected target channel, but pay the cost of sensing time. By contrast, the proactive spectrum handoff avoid the sensing time, but the pre-determined target channel may not be available. We will provide a preemptive resume priority M/G/1 queueing network model to analyze in which condition that the reactive- or proactive-sensing spectrum handoff should be used dependent of sensing time.

Seamless handoff across heterogeneous access networks using a handoff controller in a service control point

Abstract: In a telecommunications network in which a mobile handset is capable of communicating in both an IP domain and a non-IP domain, the handoff of an existing communications session between the mobile handset and a fixed user is facilitated by a handoff controller implemented in a service control point The handoff controller implements different handoff methods depending on the status of the fixed user and the transition of the mobile user Additionally 80221 Media Independent Handover Function in conjunction with SIP is used to facilitate handover between IP and Non-IP points in the system

Fast inter-ap handoff using predictive authentication scheme in a public wireless lan

Abstract: Recently, wireless LAN systems have been widely deployed for public mobile Internet services. Public wireless LAN system can provide high speed Internet connectivity using portable devices such as laptop computers, Personal Digital Assistants (PDA), etc. In the public wireless LAN systems, reliable user authentication and mobility support are essential issues. However, re-authentication during handoff procedures causes long handoff latency and this affects the quality of service in real-time multimedia applications. In this paper, we proposed a fast Inter-AP handoff scheme based on a predictive authentication method. In our scheme, a mobile host entering the area covered by an AP, performs authentication procedures for multiple APs, rather than just the current AP. These multiple APs are selected using a Frequent Handoff Region (FHR) selection algorithm, which takes into account users' mobility patterns, service classes, etc. Since a mobile host is registered and authenticated for an FHR in advance, handoff latency resulting from re-authentication can be minimized. Simulation results show that the proposed scheme is more efficient than other schemes in terms of handoff delay and buffer requirements.