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.

Improvement of LTE Handover Performance through Interference Coordination

Abstract: An Orthogonal Frequency Division Multiple Access (OFDMA) based radio-interface is specified by 3GPP for LTE system. OFDMA provides efficient spectral efficiency by reusing complete frequency band in all cells. However it projects high inter cell interference (ICI) especially on cell borders. ICI not only minimizes the cell border throughput but also effects on the handover performance in LTE. Hard handover is standardized for LTE systems using L3-filter, hysteresis, and time-to-trigger mechanisms. The UE needs to receive error free handover command message for successful handover. This becomes critical when high interference is present on cell borders. Inter cell interference coordination (ICIC) is a technique that has been proposed to overcome ICI problems. We have investigated the improvements of LTE handover performance through ICIC. We have shown that significant gain can be achieved by the use of ICIC while maintaining very low handover rates.

Re-synchronization of temporary UE IDS in a wireless communication system

Abstract: Techniques for re-synchronizing Cell Radio Network Temporary Identifiers (C-RNTIs) in a wireless communication system are described. In one design, a user equipment (UE) sends a random access preamble for random access. A base station receives the random access preamble, assigns a Temporary C-RNTI to the UE, and sends a random access response including the Temporary C-RNTI. The UE uses the Temporary C-RNTI as a C-RNTI for itself if a valid C-RNTI is not already available. The UE discards the Temporary C-RNTI and uses the valid C-RNTI if available. The UE sends a transmission after receiving the random access response, and the transmission may include the valid C-RNTI if available. For handover, the base station (a target base station) receives a handover request from a source base station, assigns the valid C-RNTI to the UE, and sends the valid C-RNTI to the source base station for forwarding to the UE.

Dual connectivity in LTE HetNets with split control- and user-plane

Abstract: Recently, a new network architecture with split control-plane and user-plane has been proposed and gained a lot of momentum in the standardisation of Long Term Evolution (LTE) Release 12. In this new network architecture, the control-plane, which transmits system information and handles user connectivity, and the user-plane, which manages user data, are split and no longer transmitted necessarily by the same network node. This dual connectivity confers a large flexibility to the system, and allows for a more energy efficient operation and enhanced mobility management. In this paper, we present a detailed description of our dual connectivity framework based on the latest LTE-Advanced enhancements, in which macrocell-assisted (MA) small cells use different channel state information-reference signals (CSI-RS) to differentiate among each other and allow User Equipment (UE) to take adequate measurements for cell (re)selection. Taking into account the limited number of available CSI-RSs, we study the assignment problem of CSI-RSs to MA small cells, analyse CSI-RS collision and confusion issues and present simulation results to demonstrate the flexibility of the proposed network architecture.

A method of effecting handover in a mobile multilayer cellular radio system

Abstract: A method of effecting handover in a mobile telephone system comprising fixed base stations and mobile stations. The system includes several layers of radio cells, where a cell in a given layer covers several cells in a nearest underlying or subordinate layer. A mobile station moving in a microcell may find it difficult to handover to another microcell in the same cell layer, when the signal strength of the established connection in the first microcell is rapidly weakened. No information concerning the target base station can be transmitted. According to the proposed method, handover is effected to a cell in the nearest overlying cell layer, a so-called umbrella cell, either permanently (the mobile is moving quickly) or temporarily (the mobile is moving slowly). In the latter case, handover is made back to a microcell. The handover command is either transmitted from the base station of the microcell having elevated power, or from the target base station.

Cellular cordless telecommunications system

Abstract: In order to design a cellular cordless telecommunications system which makes it possible to implement a large number of performance features, for example synchronization, roaming, handover, internal links, hold, check-back, transfer etc. in the cellular cordless telecommunications system without any additional wire link between the cordless base stations in the cellular cordless telecommunications system, the cordless base stations are connected to an S0 bus (i.e., a basic access line for a multi-device configured system).