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.

Velocity-Aware Handover Management in Two-Tier Cellular Networks

Abstract: While network densification is considered an important solution to cater the ever-increasing capacity demand, its effect on the handover (HO) rate is overlooked. In dense 5G networks, HO delays may neutralize or even negate the gains offered by network densification. Hence, user mobility imposes a nontrivial challenge to harvest capacity gains via network densification. In this paper, we propose a velocity-aware HO management scheme for two-tier downlink cellular network to mitigate the HO effect on the foreseen densification throughput gains. The proposed HO scheme sacrifices the best base station (BS) connectivity, by skipping HO to some BSs along the user trajectory, to maintain longer connection durations and reduce HO rates. Furthermore, the proposed scheme enables cooperative BS service and strongest interference cancellation to compensate for skipping the best connectivity. To this end, we consider different HO skipping scenarios and develop a velocity-aware mathematical model, via stochastic geometry, to quantify the performance of the proposed HO schemes in terms of the coverage probability and user throughput. The results highlight the HO rate problem in dense cellular environments and show the importance of the proposed HO schemes. Finally, the value of BS cooperation along with handover skipping is quantified for different user mobility profiles.

Method and system for adjusting uplink transmission timing for long term evolution handover

Abstract: A method and system for adjusting uplink transmission timing when sending an initial transmission to a target cell/Node-B of an evolved universal terrestrial radio access network (E-UTRAN) immediately after handover from a source cell/Node-B of the E-UTRAN. In one embodiment, a user equipment (UE) autonomously computes and applies a timing advance (TA) value based on the current source cell/Node-B timing value, cell/Node-B beacon channel reference signal measurements and knowledge of the relative time difference, (if any), between the source and target cells/Node-Bs. In another embodiment, the UE sends a scheduling request message or real data packets with the computed TA value applied to the uplink transmission timing to the E-UTRAN via pre-allocated non-contention based uplink radio resources. In an alternate embodiment, the UE sends a scheduling request message with the new computed TA value applied to the UL transmission timing to an E-UTRAN via a synchronous random access channel (RACH).

Handover management in integrated WLAN and mobile WiMAX networks

Abstract: Recently there has been much effort, in both academia and industry, to integrate a plethora of wireless technologies in order to provide ubiquitous broadband access to mobile users. Handover management is still one of the most challenging issues to be solved for seamless integration of wireless networks. This article addresses the integration of IEEE 802.11 WLANs and IEEE 802.16 WMANs, focusing mainly on the handover management aspects. First, we describe architectures, futuristic application scenarios such as the envisioned heterogeneous multihop wireless networks (HMWNs) and moving networks, as well as the related research issues. Second, we present IEEE 802.21, a new emerging standard aimed at providing a framework for media-independent handover(MIH) among heterogeneous networks. Finally, we discuss how the MIH framework can help handover management for the integrated network.

Handoffs and Handoff Selection in a Wireless Access Network

Abstract: The present invention facilitates handoffs for a mobile terminal in a wireless access network that is capable of supporting different types of handoffs. The different handoff types may include soft handoffs and fast base station switching (FBSS). In operation, context information associated with supporting wireless communications between the wireless access network and the mobile terminal are determined. Based on whether the context information is shared between base stations involved in the handoff or transferred from one base station to another of the base stations involved in the handoff, a particular handoff type is selected from the different handoff types that are available. Selecting the specific type of handoff to use may also be based on the level of context information that is available, the actual content of the context information, application preferences, channel conditions, base station or mobile terminal capabilities, or any combination thereof.

Handover adaptation for dynamic load balancing in 3gpp long term evolution systems

Abstract: The long-Term Evolution (LTE) of the 3GPP (3rd Generation Partnership Project) radio access network is in early stage of specification. Self-tuning and self-optimisation algorithms are currently studied with the aim of enriching the LTE standard. This paper investigates auto-tuning of LTE mobility algorithm. The auto-tuning is carried out by adapting handover parameters of each base station according to its radio load and the load of its adjacent cells. The auto-tuning alleviates cell congestion and balances the traffic and the load between cells by handing off mobiles close to the cell border from the congested cell to its neighbouring cells. Simulation results show that the auto-tuning process brings an important gain in both call admission rate and user throughput.