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.

Optimal Distributed Vertical Handoff Strategies in Vehicular Heterogeneous Networks

Abstract: This paper addresses the problem of optimal vertical handoff (VHO) in a vehicular network setting The VHO objective can be minimizing the data transfer time or alternatively minimizing the cost of transmitting traffic As a framework for performance evaluations, we first analyze a heterogeneous network consisting of a wide-area cellular network interworking with wireless local area networks (WLAN) with fixed inter-distance between access points (APs) placed along roadsides We further analyze a scenario with random inter-distance between WLAN APs In both aforementioned cases, only Vehicle-to-Infrastructure (V2I) capability is assumed We show that in order to minimize the cost of transmission or alternatively transmission time, performing VHOs is an appropriate choice at lower speeds, whereas it would be better to avoid VHO and stay in the cellular network at higher speeds We further generalize our study, to investigate the VHO strategies in a random inter-distance scenario with both V2I and Vehicle-to-Vehicle (V2V) communication capabilities We demonstrate that the combination of WLAN plus cellular plus ad hoc networking outperforms any other networking strategies considered in this work in terms of transmission times and transmission costs The presented results provide insightful guidelines for optimal VHO decision making based on the characteristics of the network as well as the user mobility profile

Static simulator for studying WCDMA radio network planning issues

Abstract: A static radio network simulator for studying various topics of 3rd generation WCDMA radio network planning is presented. The simulator allows analyzing coverage, capacity and quality of service related issues. Input to the simulator is the network scenario and the user information as a mobile station map. The uplink and downlink are separately analyzed and the outputs are presented in form of maps of best server, number of users, served traffic, SHO areas, AS size, SHO statistics for the area and for the users, Perch C/I plots. In the analysis, impact of the 3rd generations fast power control and soft(er) handover (SHO) possibility are taken into account by importing link level simulations into the analyses. The whole simulator is entirely based on Matlab(R) software.

Dynamic offset threshold for diversity handover in telecommunications system

Abstract: A telecommunications system has a source base station (BSS) and a destination base station (BSD), and a handover unit (100) having a dynamic offset threshold determination unit (102) which establishes a dynamic offset threshold for starting soft handover. When the dynamic offset threshold for soft handover is exceeded, a preliminary portion of a handover sequence is initiated at the destination base station. The preliminary portion of the handover sequence is initiated so that a time-critical handover sequence activity (such as L1 uplink synchronization) is well underway, if ot completed, by the time the soft handover is actually needed. The dynamic offset threshold for starting handover is based on a probability that the mobile station will engage in the handover. The probability is a statistical probability that handover will actually occur based on handover history of other mobile stations previously and similarly traveling and of the same signal strength. Another portion of the soft handover sequence (e.g., a remaining portion of the soft handover sequence) is initiated when the signal strength from the destination base station as received at the specified mobile station has a predetermined relationship to a fixed offset threshold.

Balancing load of cells in inter-frequency handover of wireless communications

Abstract: The present invention provides a method and an apparatus for allocating frequency bands associated with a multi-band network across a first and a second cell in a communications system. The method comprises determining a load parameter associated with the first and second cells in the communications system, selecting a target cell among the first and second cells for a mobile wireless device for transferring the mobile wireless device from a first frequency band to a second frequency band based on the load parameter of the first and second cells. In one embodiment, selection of an appropriate frequency band may be realized for a mobile wireless device in a multi-band network based on measurements of pilot channel properties and a load parameter to take into account a cell load of a target set of cells for an inter-frequency handover. This integration of the cell load for ranking, selection and transfer of user to a target cell from an overloaded cell may prevent unnecessary inter-frequency handover of users to cells with a relatively higher load, resulting in an increase in overall system capacity as well as quality of service.