57 results about "Handoff latency" patented technology

Beam selection is provided. A method for handover in a mobile station includes sending a scan request message for scanning a downlink (DL) beam with respect to a serving base station (BS) and a neighboring BS, to the serving BS, and receiving a scan response message; determining the DL beam for the MS by performing scanning with the serving BS and the neighboring BS based on the scan response message; sending a scan report message comprising a result of the scanning to the serving BS; when receiving an air-HO request message from the serving BS, generating an air-HO response message comprising information of a neighboring BS to which the MS hands over based on the air-HO request message; performing beam selection with the neighboring BS of the handover based on the air-HO request message; and performing the handover.

In accordance with the present invention, computer implemented methods and systems are provided for reducing handoff latency in a wireless network. In response to detecting that a handoff is necessary, the present invention uses a selective scanning algorithm that includes the use of a channel mask and/or a caching algorithm for detecting one or more new access points.

Embodiments of the present invention includes a handover processing method, a source eNB, a neighboring eNB and a network communication system. In one embodiment of the handover processing method, a source eNB selects a target eNB from neighboring eNBs that can accept a handover request from a mobile terminal, and notifies a selection result to the mobile terminal; if handover information corresponding to the mobile terminal is received by an neighboring eNB that can accept the handover request of the mobile terminal within a preset handover waiting time, the neighboring eNB determines that it is a target eNB and cooperates with the mobile terminal to perform a handover; otherwise, the neighboring eNB determines that it is a prepared eNB and reduces its resources reserved for the mobile terminal. The present invention can effectively improve the successful handover probability.

A method and apparatus managing a list of base stations (“BSs”) for which a mobile station (“MS”) can establish an optimal communications channel are disclosed. In accordance with the teachings disclosed herein, a MS acquires suitable parameter information (“information”) and bases a subsequent switching decision based upon such information. Suitable parameters comprise cell loading and/or service priority, and MS needs. Such information comprises, for example, a number of BS users, switching latency associated with a particular BS, applications available by a BS, available code space, and a number of MSs for which a particular BS can provide resources. A MS decision to switch from a first BS to a second BS is predicated upon the acquired information.

In the public WLAN systems, reliable user re-authentication for mobility support is an essential step. However, re-authentication during handoff procedures causes long handoff latency which deteriorates the quality of service specifically for real-time multimedia applications. One possible solution is to authenticate the Mobile Node (MN) in advance with all the neighboring Access Points (APs) and distribute the Session Keys to them. However, the key issue is how to optimally and efficiently select the neighboring APs. In the preferred embodiments, we propose a system that takes into account the user current “Geo-Location”, “Mobility Pattern” and “Application Running on MN”; estimates the “Expected Mobility Zone” (EMZ) and selects an appropriate set of candidate APs corresponding to the MN's geo-location. The EMZ may comprise of APs belonging to “Intra-domain”, “Inter-domain” or “Inter-technology Networks” (e.g., WLAN, WiMAX, and Cellular etc). The system assumes that not only the Mobile Nodes but also the Fixed Nodes (APs or Base Stations) are capable of knowing their Geo-Location Coordinates X, Y, Z. This capability may come either by integrating GPS receiver or through any other alternate, state of the art or future positioning technologies in the APs.

An apparatus dynamically assigns external home agent (HA) for VPNs and a method for the same is proposed. The apparatus establishes VPN between an internal network and at least one external network, whereby a mobile node (MN) can roam in the external network with security. The external HA closest to the MN in the visited external network is selected for mobility management of the MN. The MN only needs to register with the same external HA when roaming in the same external network. The handoff latency and end-to-end latency for a roaming MN, therefore, could be reduced significantly. It will also not reestablish the IPsec tunnel within the same external network.

Techniques are disclosed relating to register caching techniques for thread switches. In one embodiment, an apparatus includes a register file and caching circuitry. In this embodiment, the register file includes a plurality of registers and the caching circuitry is configured to store information that indicates threads that correspond to data stored in respective ones of the plurality of registers. In this embodiment, the apparatus is configured to store, at a point in time at which a first register of the plurality of registers includes first valid data corresponding to a first thread, second valid data corresponding to a second thread in a second register of the plurality of registers. In some embodiments, the disclosed techniques may reduce context switch latency, reduce pressure on a data cache, and/or allow smaller slices of thread execution, for example.

Handoff of (i) a mobile wirelessly communicating device—a mobile—between (ii) a plurality of stationary base stations within cells within a domain of (iii) a stationary gateway router all within (iv) a communications network based on the Internet Protocol (IP) is without interchange of control, and responsive to the mobile, only. The gateway router assigns to the mobile at a time before the handoff IP addresses suitable for the mobile to connect to the gateway router through all the plurality of base stations of the domain. Unilaterally deriving a handoff decision to switch base stations, the mobile directs its wireless communications link to a new base station where signal level registration is performed. Responsive to a link layer trigger at the new base station, the gateway router is informed of the handoff, and both the router and the mobile independently construct the mobile's new IP address. Handoff latency is typically 40 ms.

Provided is a method and apparatus for decreasing a handover latency time using a context exchange between a mobile terminal (MT) and a Media Independent Handover Server (MIHS). The method used by the MT for decreasing handover latency between a first network and a second network includes when a handover is performed from the first network to the second network, transmitting to the MIHS information required for first network communication as context; and when a handover is performed from the second network to the first network, receiving from the MIHS first network access information comprising the context through the currently used second network. Accordingly, the MT can reduce a Vertical Handover (VHO) latency time and simultaneously consume almost the same power as a single mode terminal.

An apparatus dynamically assigns external home agent (HA) for VPNs and a method for the same is proposed. The apparatus establishes VPN between an internal network and at least one external network, whereby a mobile node (MN) can roam in the external network with security. The external HA closest to the MN in the visited external network is selected for mobility management of the MN. The MN only needs to register with the same external HA when roaming in the same external network. The handoff latency and end-to-end latency for a roaming MN, therefore, could be reduced significantly. It will also not reestablish the IPsec tunnel within the same external network.

A method for minimizing handoff latencies when a handoff is performed in a wireless network. An access point (AP) or base station associated to a current wireless station (STA) allows information required for a reassociation to the STA to be propagated to handoff-capable neighboring APs or base stations. When the STA moves, a neighboring AP or base station performs the reassociation to the STA on the basis of context. When a handoff procedure is performed, the time taken to receive context of a corresponding STA is reduced, such that a fast handoff can be implemented.

A wireless communication device is disclosed that is capable of performing efficient measurements of secondary radio access technologies (RATs). The device includes multiple receiver chains. While operating in a first RAT, the device receives a measurement gap in order to perform measurements. Even though the measurement gap may be too small to adequately measure the other RAT, the device controls one of the receiver chains to measure the other RAT during a time period that overlaps with the measurement gap. In addition, when preparing for an inter-RAT handoff, the device controls one of the receiver chains to perform measurements regardless of whether a measurement gap has been received. In this manner, measurements of alternative RATs are efficiently performed, and handoff latency is significantly reduced.

This invention employs an inherent tradeoff in a radio bearer dependent data handling method for intra-E-UTRA handoffs. For user equipment using real time data, the source node forwards to the target node not yet acknowledged real time service data units and disconnects. This makes the handoff latency short at the expense of data traffic between nodes. For user equipment not needing real time data, the source node continues to receive user equipment acknowledgements during a time out period and only forwards service data units acknowledged during the time out period. This reduces X2 interface traffic between the source and target nodes but extends the handoff latency.

To reduce handover latency experienced by a user using a user equipment that is served for offloaded user data traffic by a first small cell, a handover between a first macro cell deploying the first small cell and a second macro cell deploying a second small cell is triggered when information indicating that the user equipment has associated with the second small cell not deployed by the first macro cell is received.

A communication system includes devices configured to communicate with each other through a temporal sequence of frames. Each of these frames includes multiple sub-channels. Note that a given device in the devices is configured to select sub-channels to reserve based on a nearest-neighbor spacing between the sub-channels to be reserved and/or a switching latency between data in-flow to the given device and data out-flow from the given device. Furthermore, the given device is configured to dynamically reserve the selected sub-channels on a frame-by-frame basis for up to N frames.

A circuit for switching clock signals with logic devices using a glitchless clock multiplexer optimized for synchronous and asynchronous clocks. The circuit comprises an asynchronous clock group and one or more synchronous clock group(s). The asynchronous group comprises a plurality of high frequency glitchless control (HFGC) blocks for asynchronous clock sources. Each synchronous group comprises a plurality of HFGC blocks for synchronous clock sources. The circuit comprises a multiplexer for receiving delayed input clock signals from HFGC blocks for asynchronous clock sources and from HFGC blocks for synchronous clock sources. A switching latency from a first input clock signal belonging to a synchronous group to a second input clock signal belonging to the same synchronous group is one clock cycle or less of the second input clock signal. Switching latency is the period in which no clock pulse appears at the final output of the circuit.

The present invention discloses a multimedia broadcast device which can reduce the channel switch time; the present invention is used for reducing the channel switch time of a user terminal in a multimedia broadcast system; when the channel is switched, the length of the switch frame is confirmed according to the maximum value of the total length of a group of complete data frame which every processing module in the user terminal of the multimedia broadcast system can process independently. The switch frame length is taken as the benchmark, every processing module at the system side aligns the self-processing data frames and arranges a group of data frames which can be processed independently by the corresponding processing modules at the user terminal within one switch frame length. As for the data frame which is output within one switch frame by the former module, the next processing module processes the data frame and outputs the corresponding data frame within one switch frame length. The multimedia broadcast system of the present invention, by aligning the switch frame boundary of every processing module at the system side, can reduce the channel switch time at the user terminal and realize the fast switch of channels.