Abstract: This paper presents a self-optimizing algorithm that tunes the handover (HO) parameters of a LTE (Long-Term Evolution) base station in order to improve the overall network performance and diminish negative effects (call dropping , HO failures). The proposed algorithm picks the best hysteresis and time-to-trigger combination for the current network status. We examined the effects of this self-optimizing algorithm in a realistic scenario setting and the results show an improvement from the static value settings.

Abstract: Techniques for performing forward handover in a wireless communication system are disclosed. In one aspect, a user equipment (UE) transmits a connection request to a target eNodeB. The connection request may be transmitted when the UE detects a connection failure in a communication with a source eNodeB. The UE receives a connection response from the target eNodeB in response to the target eNodeB requesting handover preparation information from the source eNodeB. In another aspect, a target eNodeB may receive a connection request from a user equipment (UE) and transmit a radio link failure (RLF) recovery request message to a source eNodeB to prompt the source eNodeB to initiate handover of the UE from the source eNodeB.

Abstract: Current IP-level mobility management protocols are unable to satisfy the stringent handover latency requirements for supporting real-time multimedia services between different domains in a high-speed vehicular environment. This paper proposes an inter-domain handover scheme for Proxy Mobile IPv6 (PMIPv6) with a new network entity, called intermediate-mobile access gateway (iMAG). The iMAG is located between the home and the foreign domains and is connected to both domains. The proposed scheme is a proactive handover approach that performs the inter-domain L3 handover in advance before the inter-domain L2 handover while the Mobile Node (MN) is still connected to the iMAG in the home domain. Therefore, the proposed scheme enables the inter-domain handover latency to reduce as low as the intra-domain handover latency. Numerical analysis and simulation results demonstrate that the proposed scheme is able to support seamless service continuity in inter-domain handovers. Copyright © 2009 John Wiley & Sons, Ltd. This paper proposes an inter-domain handover scheme for Proxy Mobile IPv6 (PMIPv6) with a new network entity, called intermediate-mobile access gateway (iMAG) which is connected to both the home and the foreign domains. The proposed scheme is a proactive handover approach that performs the inter-domain L3 handover in advance before the inter-domain L2 handover while the Mobile Node (MN) is still connected to the iMAG in the home domain. Therefore, the proposed scheme enables the inter-domain handover latency to reduce as low as the intra-domain handover latency. Copyright © 2009 John Wiley & Sons, Ltd.

Abstract: An application mobility-management entity (“AME”) in a radio-access network detects movement of a mobile device and routes application data for already-active application streams associated with the mobile device to the device's new location by establishing a connection to a second AME in the radio-access network. The second AME merges forwarded application data from/to the first AME for previously active application streams with the new application streams (e.g., new TCP connections) locally and forwards to/from the mobile device through the radio access network elements.

Abstract: There is provided initiating a handover of a connection of user equipment, the connection comprising a path from an access network to a core network and switching the path to the core network on the basis of data received on the connection exceeding a threshold.

Abstract: Disclosed is a method in which in case where it is inappropriate for a particular Home (e)NodeB providing a service to a particular UE to continue to provide the service on the ground of a changed status, such as overload, temporary drop due to maintenance, expiry of CSG membership for the UE, increase of temporary interference, policy change, or the like, the Home (e)NodeB transmits information on a cause that the UE performs a handover to another base station to an control entity within a network. Furthermore, it is allowed for the entity within the network to store information on the cause. In addition, if the status of the particular Home (e)NodeB is changed, then the entity within the network is allowed to perform a reverse handover for the UE to the particular Home (e)NodeB on the basis of the information on the changed status and the information on the cause.

Abstract: Methods and apparatus, including computer program products, are provided for D2D handovers. The method may include sending to a target base station a handover request message including a proposed common identifier for a device-to-device pair and a proposed allocation of radio resources for the device-to-device pair; receiving, from the target base station in response to the handover request message, a handover request reply message including a confirmation of the proposed allocation and of the proposed common identifier; sending to a first device of the device-to-device pair a handover command including the proposed allocation and the proposed common identifier; receiving, from a second device of the device-to-device pair, a measurement report representative of the target base station; and determining whether to initiate a handover of the second device to the target base station, wherein when the handover is initiated, the first device of the device-to-device pair and the second device of the device-to-device pair are handed over to the target base station. Related apparatus, systems, methods, and articles are also described.

Abstract: Handover parameter settings are automatically adapted in access points in a system to improve handover performance. Reactive detection techniques are employed for identifying different types of handover-related failures and adapting handover parameters based on this detection. Messaging schemes are also employed for providing handover-related information to access points. Proactive detection techniques also may be used for identifying conditions that may lead to handover-related failures and then adapting handover parameters in an attempt to prevent such handover-related failures. Ping-ponging may be mitigated by adapting handover parameters based on analysis of access terminal visited cell history acquired by access points in the system. In addition, configurable parameters (e.g., timer values) may be used to detect handover-related failures.

Abstract: A method and apparatus are described for processing emergency calls by simplifying call setup procedures and minimizing call setup delay. In one scenario, a system information (SI) broadcast may include emergency services support information that conveys various emergency call network support levels and setup procedures. The SI broadcast is decoded to retrieve system parameters used to process an emergency call. The SI broadcast may include a bitmap or at least one information element (IE), that indicates the various emergency call network support levels. In another scenario, an extended service request message indicating circuit switched fallback (CSFB) for an emergency call is transmitted to a packet switched (PS) radio access technology (RAT) network during a PS session. An inter-system change is performed from the PS RAT network to a circuit switched (CS) RAT without a PS handover, and a CS emergency call is initiated via the CS RAT network.

Abstract: This paper investigates how to characterize the effect of multiple spectrum handoff delay on the extended data delivery time of the secondary users' connections in cognitive radio (CR) networks. Whenever a primary user appears, the spectrum handoff procedures are initiated for the interrupted secondary users. Through spectrum sensing, the secondary user can reactively decide the target channel for spectrum handoff to resume its unfinished transmission. Clearly, many interruptions from the primary users will result in multiple handoffs, thereby increase the extended data delivery time of a secondary connection. In this paper, we develop a Markov transition model integrating with the preemptive resume priority (PRP) M/G/1 queueing network to characterize the multiple handoff delay, resulting from the sensing time, the handshaking time, the channel switching time, and the waiting time. The analytical results can facilitate the designs of admission control rules for the secondary users subject to their latency requirements and provide a framework to determine whether the spectrum sensing technology can effectively shorten the extended data delivery time under various traffic arrival rates and service time as well as sensing time.

Abstract: Systems and methods of operating multimode 3G/4G communications devices in an overlapping 3G/4G coverage area (e.g., WiMAX or LTE/CDMA-EvDO) include determining a loading condition of the 3G and 4G base stations. If the 3G and 4G base stations are lightly loaded, one or more 4G Channel Quality Indicators (CQI) are compared with one or more corresponding 3G Data Rate Control (DRC) indices to determine which of the 3G and 4G networks allows a higher data throughput. The dual mode communications device is handed off to a 4G base station associated with the 4G coverage if the 4G network allows the higher data throughput; otherwise, the dual mode communications device is handed off to a 3G base station. User priorities, application categories, and/or MIMO and diversity modes may be used to determine handoff if the base stations are more than lightly loaded.

Abstract: As part of carrier assignment and configuration for multicarrier wireless communications, a single uplink (UL) primary carrier may provide control information for multiple concurrent downlink (DL) carriers. Optionally, control information for each DL carrier may be transmitted over paired UL carriers. Carrier switching of UL and/or DL carriers, including primary and anchor carriers, may occur during normal operation or during handover, and may occur in only the UL or only the DL direction. A unidirectional handover is performed when only an UL carrier or only a DL carrier is switched as part of a handover. Switching of UL and/or DL carriers may be from one component carrier or a subset of carriers to another component carrier, another subset of carriers, or all carriers in the same direction.

Abstract: Systems and methodologies are described herein that facilitate techniques for design of relay backhaul to support mobility of relay nodes in a wireless communication system. According to various aspects herein, techniques are provided to enable and support the use of mobile relays and to facilitate handover of mobile relays between respective donor cells. More particularly, techniques are provided herein for relay backhaul control channel assignment associated with hand in or hand out of mobile relays, access/backhaul resource partitioning for mobile relays, and management of quality of service (QoS) requirements associated with a relay handover.

Abstract: The challenge of elimination of redundant handovers is getting more significant while femtocells with small radius are deployed in networks. The utilization of the femtocells results to more frequent initiation of a handover procedure. This paper focuses on an adaptation of actual level of hysteresis margin according to the position of the user in a cell. The hysteresis margin is commonly used parameter for elimination of redundant handovers. The purpose of this paper is to propose mechanism with minimum requirements on conventional network and user’s equipment and with a simple implementation. Evaluations of proposal in term of efficiency of the redundant handovers reduction as well as an impact on the user’s throughput in 4G wireless networks are carried out. The results show significant reduction of the amount of handovers while reducing the impact on the throughput.

Abstract: The present invention relates to a method and a device for time synchronization of an RBS which has lost its GPS signal. The method in the time synchronization device comprises retrieving from the first radio base station a first timing advance value (710) used by the user equipment to adjust its transmission timing before the handover, and a measurement of a reception timing (720) of a random access preamble. The random access preamble is transmitted from the user equipment to the second radio base station during synchronization. The method also comprises retrieving (730) from the second radio base station a second timing advance value used by the user equipment to adjust its transmission timing after the handover, and determining (740) a time synchronization offset between the first and second radio base station based on the retrieved first timing advance value, the second timing advance value, and the measurement of the reception timing.

Abstract: A heterogeneous communication system enables femto Access Points (APs) to advertise handoff related information on a first Radio Access Technology (RAT), such as for receipt by a multi mode mobile device (e.g., a mobile device capable of operation on a plurality of RATs), wherein the handoff related information permits the multi mode mobile device to identify the femto access point on a second RAT. The multi mode mobile device can be connected to a macro node (e.g., a macro base station, an evolved Base Node, etc.) using the first RAT via a Wireless Wide Area Network (WWAN) air-interface (e.g., 1×, HRPD, eHRPD), while independently reading/decoding overhead messages on the second RAT for connection thereto (e.g., connection to the femto access point on the second RAT.) The second RAT can be another WWAN, a Wireless Local Access Network (WLAN) or a Personal Access Network.

Abstract: Next-generation wireless networks should be able to coordinate and integrate different communication systems. It has been a challenging problem to support a seamless handover in these diverse wireless network environments. Link level triggers can provide information about events which can help handover decision and layer 3 entities better streamline their handover related activities. In most conventional layer 2 triggering approaches, a pre-defined threshold for a specific perspective such as the received signal strength is used. This may cause too late or too early handover executions. In this paper we propose a new predictive handover framework that uses the neighbor network information to generate timely the link triggers so that the required handover procedures can appropriately finish before the current link goes down. First we estimate a required handover time for the given neighbor network conditions, then using a predictive link triggering mechanism the handover start time is dynamically determined to minimize handover costs. The handover costs are analyzed in terms of the total required handover time and the service disruption time. The numerical analysis and simulation results show that the proposed method significantly enhances the handover performance in heterogeneous wireless networks.

Abstract: Wireless systems have the capability to address broad geographic area without the costly infrastructure deployment. However, the main drawback resides in the bandwidth limitation and the coverage for single access point. The deployment of Femtocell as the promising wireless access technology becomes one of the possible solution. In this paper the handover procedure in femtocell network is studied. The 3GPP LTE based handover is analysed in three scenarios: hand-in, hand-out and inter-FAP. In addition, the reactive and proactive handover strategy is also proposed as the handover decision policy to diminish the very frequent and unnecessary handovers.

Abstract: Systems and methodologies are described herein that facilitate efficient transfer of quality of service (QoS) context during inter-radio access technology (RAT) handovers. In particular, techniques are described herein for establishing rules for whether a user equipment unit (UE) or an associated network should establish QoS for a mixed-mode application, identifying flow to bearer mappings when translating QoS across an inter-RAT handover, mapping QoS parameters of respective RATs, mitigating QoS depreciation upon multiple handovers, performing one or more actions if QoS is not acceptable in a new RAT, maintaining QoS during tunnel mode, and handling scenarios in which a UE moves between a RAT using network-initiated QoS and a RAT using UE-initiated QoS.

Abstract: We deal with a cost-based adaptive handover hysteresis scheme for the horizontal handover decision strategies, as one of the self-optimization techniques that can minimize the handover failure rate (HFR) in the 3rd generation partnership project (3GPP) longterm evolution (LTE) system based on the network-controlled hard handover. Especially, for real-time operation, we propose an adaptive hysteresis scheme with a simplified cost function considering some dominant factors closely related to HFR performance such as the load difference between the target and serving cells, the velocity of user equipment (UE), and the service type. With the proposed scheme, a proper hysteresis value based on the dominant factors is easily obtained, so that the handover parameter optimization for minimizing the HFR can be effectively achieved. Simulation results show that the proposed scheme can support better HFR performance than the conventional schemes.

Abstract: The present invention introduces a method for the network to optimize the route for user's local IP access, without affecting the access to operator's core network. With this mechanism, no excessive signalling is needed for the optimization. The present invention is also applicable to the corporate network that has multiple home NodeBs or home eNodeBs. Finer grain control on the services to be provided over different home NodeB or home eNodeB is also possible. Further, path optimization and continuation of the service upon handover can be controlled, and hence flexibility of the service can be secured.

Abstract: Hierarchical macro/femto-cell networks are considered as a promising technology for the improvement of indoor coverage and network capacity. In these emerging networks, handoff procedures for a mobile station moving from a macrocell to a femtocell should be provided to maximize the advantages of femtocells with respect to user satisfaction and system performance. Therefore, we propose an efficient handoff decision algorithm that can be utilized in the situation where a user enters the coverage area of the femtocell. The main idea of the proposed algorithm is to combine the values of received signal strength from a serving macro BS and a target femto BS in the consideration of large asymmetry in their transmit powers. Numerical results show that there is a significant gain in view of the probability that the user will be assigned to the femtocell while keeping the same level of the number of handoffs.

Abstract: A handover method and apparatus for facilitating a handover of a user equipment to a femto cell in a wireless communication system supporting both the femto and macro cells When a handover condition is detected, the user equipment acquires identity information of a target femto cell base station from system information transmitted by the target femto cell base station, decides whether to handover to the target femto cell base station, based on the identity information; and transmits a measurement report message including the identity information to a serving base station of the user equipment, when the handover is to be made

Abstract: The nurse-to-nurse handover is not taught formally during training, yet it is one of the most important rituals of the nursing shift. This article focuses on the structure and function of change-of-shift reports and lists the events that occur within them, describing the locations of the handover process and the mode of communication involved. The problems that can occur during handover are discussed and solutions are proposed.

Abstract: Handover is one of the key components in cellular network mobility management and has the most stringent latency requirement on service interruption time since the end-user experience is majorly determined by it In the design of IMT-Advanced systems, the scalability and flexibility to support various 4G deployments is also very crucial while meeting the latency requirement on handover This article presents the state-of-the-art handover schemes considering various deployment scenarios in IMTAdvanced candidate systems with a focus on IEEE 80216m based next-generation WiMAX networks and 3GPP LTE-Advanced Also, to minimize and optimize handover latency to fulfill the requirement for quality of service during handover, various procedural advanced handover schemes are being developed, proposed, and analyzed by IEEE 80216m and 3GPP Handover schemes in IEEE 80216m and 3GPP provide lower link layer handover latency while providing the required QoS level than the existing link layer handover schemes

Abstract: A method of dynamic resource transaction in wireless OFDMA systems is proposed. In macro-femto overlay network architecture, network and traffic condition varies dynamically. Dynamic resource transaction is a powerful mechanism to achieve effective interference mitigation and flexible radio resource management to enhance resource utilization as well as to improve link performance. Dynamic resource transaction can be performed by signaling or message exchange through backhaul network or air-interface connections. The signal or message through backhaul network can be directly exchanged among multiple base stations or be routed through a centralized self-organizing network (SON) server. In one embodiment, dynamic resource transaction is used to achieve adaptive reservation region configuration, a solution to avoid interference and frequent handover for high-speed mobile stations.

Abstract: In Long Term Evolution (LTE) networks, Mobility Robustness Optimization (MRO) and Mobility Load Balancing (MLB) are two important functions to auto-optimize the network performances. There is a close correlation between them, as they both choose adjusting handover parameters as optimization actions. The conflict may occur between the two functions when they adjust the same handover parameter in opposite directions. This can not improve the performances but waste network resources. In this paper, we present a novel scheme to solve the problem. In order to prevent the occurrence of the conflict, we set an allowed range for MLB in which the handover problems can be prevented. Analyses and simulation results demonstrate that the proposed scheme can effectively solve the conflict problem and improve the performances of both functions.

Abstract: A method and system for managing a plurality of network bearers in a wireless communication network is provided. The method includes identifying at least one of an initiation or an update of an instance of an application session. The method then generates an identifier associated with said instance of the application session. Further, the method assigns said identifier to each of the plurality of network bearers established as a result of said identified initiation or identified update of said instance of the application session. In an embodiment, the method uses the said identifier for managing communication during handover from a first communications network to a second communications. The method manages both video bearers and the voice bearers during the handover based on the said identifier.