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.

Communications system handoff operation combining turbo coding and soft handoff techniques

Abstract: Communication systems, including, for example, cell-based mobile communication systems, multiple satellite communication systems, or multibeam satellite systems, require reliable handoff methods between cell-to-cell, beam-to-beam, or satellite-to-satellite respectively. Recent measurement of a CDMA cellular system indicates that the system is in handoff about 30 % to 50 % of an average call period. Therefore, system reliability during handoff is one of the major system performance parameters and eventually becomes a factor in the overall system capacity. The present invention advantageously relates to novel and improved techniques for handoff in cellular communications, multibeam and multisatellite systems. The present invention combines the soft handoff mechanism with a code diversity combining technique (i.e., combining signals from multiple sources), a packet combining technique (i.e., combining multiple signals), and an iterative decoding algorithm (e.g., Turbo Coding (502)).

Radio base station device and mobile communication system

Abstract: When carrying out a downlink handover, a source base transceiver station from which a mobile node is moving receives packets to be transmitted, via a wireless section, to the mobile node from an IP network, and copies and transfers them to a destination base transceiver station to which the mobile node is moving. On the other hand, when carrying out an uplink handover, the source base transceiver station compares the reliability of transport blocks which are received via a wireless section, from the mobile node and which are demodulated and decoded by the local station with that of transport blocks which are received via an IP network, from another base transceiver station and which are demodulated and decoded thereby, packetizes selected transport blocks with a better quality, and transmits them to a communications-partner node according to a route table, thereby implementing distribution of traffic via the IP network.

Predictive mobility support for QoS provisioning in mobile wireless environments

Abstract: With the proliferation of wireless network technologies, mobile users are expected to demand the same quality of service (QoS) available to fixed users. This paper presents a predictive and adaptive scheme to support timed-QoS guarantees in pico- and micro-cellular environments. The proposed scheme integrates the mobility model into the service model to achieve efficient network resource utilization and avoid severe network congestion. The mobility model uses a probabilistic approach to determine the most likely cluster to be visited by the mobile unit. The admission control is invoked when a new call arrives or an existing call performs a handoff to verify the feasibility of supporting the call. The performance of the proposed schemes is compared to the shadow cluster scheme. The performance of the proposed scheme under different traffic patterns is also presented.

Handoff of a multimedia call session using background network scanning

Abstract: A method and system supporting handoff of a multimedia call session using background network scanning is disclosed. A mobile multimedia handset may engage in the exchange of a multimedia information stream via a first wireless network, and may sniff a portion of radio frequency spectrum for a second wireless network. Information about available services and network quality of service for the second network may be received by querying the second wireless network or from advertising by the second wireless network. Hand-off between the two networks may be based upon the results of the comparison and one or more user-defined criteria, and the handoff may be synchronized according to predefined events in the stream of multimedia information.