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.

Performance of handoff algorithm based on distance and RSSI measurements

Abstract: The performance of a proposed handoff algorithm based on both the distance of a mobile station to neighboring base stations and the relative signal strength measurements is evaluated. The algorithm performs handoff when the measured distance from the serving base station exceeds that from the candidate base station by a given threshold and if the measured signal strength of the adjacent base station exceeds that of the serving base station by a given hysteresis level. The average handoff delay and average number of handoffs are used as criteria for performance. Numerical results are presented to demonstrate the feasibility of the distance-based handoff algorithm, including results for an additional criterion based on relative signal strength. The proposed algorithm is compared with an algorithm based on absolute and relative signal strength measurements and with a solely distance-based algorithm. It is found that the proposed handoff algorithm performs well in a log-normal fading environment when the distance estimate error is modeled by wide-sense stationary additive white Gaussian noise.

Method and apparatus providing handoff of a mobile station between base stations using parallel communication links established with different time slots

Abstract: The soft handover of a channel or a base station according to the invention functions especially well in a TDMA system with a high TDMA milo. For the time of preparation of handover parallel physical links are formed between the mobile station (MS) and two or more base stations (BTS1, BTS2), whereby these base stations transmit the same signal to the mobile station (MS) in different time slots, and possibly in a different frequency.

Access control for macrocell to femtocell handover

Abstract: Access to a femtocell can be controlled as part of handover of a mobile device from macrocell to femtocell. Macro network platform issues a handover (HO) request towards femto network platform and a single virtual femto node, which represents a plurality of femto access points (APs). Location estimate(s) for the mobile device drives selection of a target femto AP. Selection of the target AP results in acceptance of the HO request. The mobile device also can request macro-to-femto (MTF) handover. HO neighbor list(s) is generated by decoding a network-issued identifier for each femto APs in a set of femtocells, and selectively ranking each femto AP based at least on channel quality; access privileges of the mobile device to each of the identified femto APs determines selectivity. Validation of mobile device's access right(s) drives acceptance of the MTF HO request to a top ranked femto AP.

System for managing call handoffs between an aircraft and multiple cell sites

Abstract: The handoff management system maximizes the communications capacity available from terrestrial air-to-ground cellular networks, while also integrating communications capabilities from satellite air-to-ground cellular networks and terrestrial cellular communications networks. The communications capacity is maximized by dynamically allocating communications from the aircraft over multiple communications channels to multiple cells of the terrestrial air-to-ground cellular network, and to satellite air-to-ground cellular networks and terrestrial mobile networks. This approach effectively provides an increase in the call handling capacity available to any aircraft and permits a gradual transition of communications from one cell to the next cell, rather than requiring an abrupt handover of all traffic from the aircraft from one cell to the next cell.

Performance Analysis and Optimization of Handoff Algorithms in Heterogeneous Wireless Networks

Abstract: In heterogeneous wireless networks, handoff can be separated into two parts: horizontal handoff (HHO) and vertical handoff (VHO). VHO plays an important role to fulfill seamless data transfer when mobile nodes cross wireless access networks with different link layer technologies. Current VHO algorithms mainly focus on when to trigger VHO, but neglect the problem of how to synthetically consider all currently available networks (homogeneous or heterogeneous) and choose the optimal network for HHO or VHO from all the available candidates. In this paper, we present an analytical framework to evaluate VHO algorithms. Subsequently, we extend the traditional hysteresis based and dwelling-timer based algorithms to support both VHO and HHO decisions and apply them to complex heterogeneous wireless environments. We refer to these enhanced algorithms as E-HY and E-DW, respectively. Based on the proposed analytical model, we provide a formalization definition of the handoff conditions in E-HY and E-DW and analyze their performance. Subsequently, we propose a novel general handoff decision algorithm, GHO, to trigger HHO and VHO in heterogeneous wireless networks. Analysis shows that GHO can achieve better performance than E-HY and E-DW. Simulations validate the analytical results and verify that GHO outperforms traditional algorithms in terms of the matching ratio, TCP throughput and UDP throughput.