Abstract: A system for providing handoff for a mobile devices comprising a mobile phone programmed to automatically handover between differing data bearers and to optimally detect those bearers in a roaming environment keeping power consumption to a minimum. Repeating means for these mobile devices to extend the range of coverage and the protocol for that coverage.

Abstract: Radio resource management (RRM) plays a major role in Quality of Service (QoS) provisioning for wireless communication systems. The performance of RRM techniques has a direct impact on each user's individual performance and on the overall network performance. Arriving (new and handoff) calls are granted/denied access to the network by the call admission scheme (CAC) based on predefined criteria, taking the network loading conditions into consideration. CAC in wireless networks has been receiving a great deal of attention during the last two decades due to the growing popularity of wireless communications and the central role that CAC plays in QoS provisioning in terms of the signal quality, call blocking and dropping probabilities, packet delay and loss rate, and transmission rate. In the first and second generation of wireless systems, CAC has been developed for a single service environment. In the third generation and beyond wireless systems, multimedia services such as voice, video, data, and audio are to be offered with various QoS profiles. Hence, more sophisticated CAC schemes are developed to cope with these changes. This article provides a comprehensive survey of CAC schemes in modern wireless networks.

Abstract: A telephone system supports communication with user devices over both a cellular radio network as well as over an Internet Protocol (IP) network, and enables roaming and active call handoff between cellular and IP domains. Components of the system interact with conventional cellular telephone systems, for example, by emulating behavior of control components, providing proxy services for conventional components, transporting cellular telephone control communication over IP connections, or by simulating cellular operating characteristics of user devices operating in an IP domain.

Abstract: In some illustrative embodiments, a novel system and method is provided that can, for example, extend concepts of pre-authentication (such as, eg, IEEE 80211i pre-authentication) so as to operate across networks or subnetworks (such as, eg, IP subnets) In preferred embodiments, a novel architecture includes one or both of two new mechanisms that substantially improve, eg, higher-layer handoff performance A first mechanism is referred to as “pre-configuration,” which allows a mobile to pre-configure higher-layer information effective in candidate IP subnets to handoff A second mechanism is referred to as “virtual soft-handoff,” which allows a mobile to send or receive packets through the candidate IP subnets even before it is actually perform a handoff to any of the candidate IP subnets

Abstract: A good nursing handover process is a crucial part of providing quality nursing care in a modern healthcare environment. The conservation of patient data during the handover process is vital to ensure good continuity of care and safe practice. Any errors or omissions made during the handover process may have dangerous consequences. The authors observed the handover of 12 simulated patients over five consecutive handover cycles between nurses. Three handover styles were used and the amount of data loss was recorded for each style. A purely verbal handover style resulted in the loss of all data after three cycles. A note-taking style (the traditional style used in most hospital wards) resulted in only 31% of data being transferred correctly after five cycles. When a typed sheet was included with the verbal handover, data loss was minimal. Current handover methods may result in significant loss of important data that may impact on patient care. The authors recommend that prior to handover, a formal handover sheet be constructed that can be transferred as part of the handover process.

Abstract: Deployment of Voice-over IP (VoIP) and other real-time streaming applications has been somewhat limited in wireless LANs today, partially because of the high handoff latencies experienced by mobile users. Our goal in this work is to eliminate handoff latency by exploiting the potential of multiple radios in WLAN devices. Our proposed approach, called MultiScan, is implemented entirely on the client-side, and, unlike prior work, MultiScan requires neither changing the Access Points (APs), nor having knowledge of wireless network topology. MultiScan nodes rely on using their (potentially idle) second wireless interface to opportunistically scan and pre-associate with alternate APs and eventually seamlessly handoff ongoing connections. In this paper we describe our implementation of MultiScan, present detailed evaluations of its effect on handoff latency and evaluate performance gains for MultiScan-enhanced wireless clients running Skype, a popular commercial VoIP application.

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.

Abstract: Method and system to support fast hand-over of mobile subscriber stations in broadband wireless networks. In connection with a hand-over process, a determination is made to which target base station (BS) an air interface for a mobile subscriber station (MSS) is to be handed-over. Various service requirements are requested by the MSS, including a Quality of Service (QoS) level. Based on feedback from potential target BSs, a target BS for hand-over is selected. Current connection context data corresponding to current service flows provided by a serving BS is passed to the target BS to pre-provision service such that a minimal amount of re-entry messaging is required. In one embodiment, a Management Information Base (MIB) instance is maintained at each BS in a broadband wireless network. To pre-provision service, applicable connection context data are transferred between MIB instances at the serving and target BS using Simple Network Management Protocol (SNMP) messaging.

Abstract: Handover of patient care has been an ongoing problem within the health care sector. The process remains highly variable and there is a threat to patient safety. Despite the general belief that handover transitions in patient care have become routine, not enough attention or research has been directed at improving this period of care. For this reason there is a need to provide an analysis of the communication processes during handover. A study was conducted of the handover process among doctors during shift changes within a hospital setting. The results suggested a need for process change. Results revealed a handover process which was unstructured, informal and error prone, with the majority of doctors noting that there was no standard or formal procedure for handover. The research found that the majority of hospital doctors recognised the potential benefits of formalising and computerising this process.

Abstract: A method for performing a handover by a subscriber station (SS) in a broadband wireless communication system including a serving base station (BS) communicating with the SS, and at least one neighbor BS neighboring the serving BS. The SS receives downlink signals from the serving BS and the neighbor BS; measures an arrival time difference between the downlink signal received from the serving BS and the downlink signal received from the neighbor BS; and transmits the measured arrival time difference to the serving BS.

Abstract: As mobile wireless networks increase in popularity and pervasiveness, we are facing the challenge of integration of diverse wireless networks such as WLANs and WWANs. Consequently, it is becoming progressively more important to arrive at a vertical handoff solution where users can move among various types of networks efficiently and seamlessly. The ability to remain connected as a mobile device roams across different types of networks still remains an unachieved objective. Frequently, just choosing the best network to connect to, is a challenging problem due to the large number of network characteristics that need to be considered. Identifying these decision factors is therefore one of the principal objectives for seamless mobility. In this paper, we discuss the different factors and metric qualities that give an indication of whether or not a handoff is needed. We then describe a vertical handoff decision function, VHDF, which enables devices to assign weights to different network factors such as monetary cost, quality of service, power requirements, personal preference, etc.

Abstract: To provide mobile users with seamless Internet access anywhere and anytime/ there is a strong demand for interworking mechanisms between cellular networks and wireless local area networks in the next-generation all-IP wireless networks. In this article we focus on resource management and call admission control for QoS support in cellular/WLAN interworking. In specific, a DiffServ interworking architecture with loose coupling is presented. Resource allocation in the interworking environment is investigated/ taking into account the network characteristics, vertical handoff, user mobility, and service types. An effective call admission control strategy with service differentiation is proposed for QoS provisioning and efficient resource utilization. Numerical results demonstrate the effectiveness of the proposed call admission control scheme.

Abstract: The present invention provides a method and system for facilitating efficient handoff and data throughput in mobile broadband communication systems. Methods implemented by a system constructed in accordance with the principles of the present invention include selectively enabled soft handoff, performing Layer 2 bearer functions at the base station and using the mobile device to coordinate soft handoff and interference avoidance without the need for a centralized coordination function.

Abstract: Methods and messages for performing handovers between an unlicensed mobile access network (UMAN) comprising a first radio access network and a second radio access network. URR (UMA radio resource) handover messages are exchanged between a mobile station (MS) and a UMA network controller (UNC) operating in the UMAN. The MS may access the UMAN via a wireless access point (AP) that is communicatively coupled to the UNC via an IP network. The URR handover messages are sent between the MS and the UNC using an Up interface comprising a set of layered protocols over an underlying IP transport. The handover methods include both handover from a UMAN to the second radio access network, and handover from the second radio access network to the UMAN.

Abstract: Although there are various wireless access network technologies with different characteristics and performance level have been developed, no single network that can satisfy the anytime, anywhere, and any service wireless access needs of mobile users. A truly seamless mobile environment can only be realized by considering vertical and horizontal handoffs together. With the advantages of Mobile IPv6, a more comprehensive and integrated framework of heterogeneous networks can be developed. In this paper, we discuss the issues related to handoffs including horizontal and vertical handoffs. We present a scheme for integrating wireless local area network and wide area access networks, and propose a micromobility management method called HiMIPv6+. We also propose a QoS-based (quality-of-service-based) vertical handoff scheme and algorithm that consider wireless network transport capacity and user service requirement. Our prototype evaluations and the simulations show that our framework performs as expected.

Abstract: A proxy server (208) provides an anchor point for access network changes in a wireless environment. One example embodiment uses the concept of proxy server in order to preserve a uniform connectivity to a gateway service node while roaming across different networks through a handover mechanism. In one embodiment, the client connects to a proxy server through one access network (204), and the proxy server manages and keeps track of the user session toward the gateway service node. The client then connects to any packet service network, including Internet, through the proxy. When the client moves from one network to another, it indicates the change to the proxy and proxy, using a handover mechanism, switches the access network while maintaining the user session toward the gateway service node. The handover mechanism involved is efficient, with minimal messaging overhead, and preserves the application layer IP address of the client. Therefore, the data connections do not suffer from interruptions due to roaming through different networks and the service is seamlessly continued.

Abstract: The handoff management system maximizes the communications capacity available from terrestrial air-to-ground cellular networks, while also integrating communications capabilities from satellite air-to-ground cellular networks and terrestrial cellular communications networks. The communications capacity is maximized by dynamically allocating communications from the aircraft over multiple communications channels to multiple cells of the terrestrial air-to-ground cellular network, and to satellite air-to-ground cellular networks and terrestrial mobile networks. This approach effectively provides an increase in the call handling capacity available to any aircraft and permits a gradual transition of communications from one cell to the next cell, rather than requiring an abrupt handover of all traffic from the aircraft from one cell to the next cell.

Abstract: The present invention is related to transmitting quality of service (QoS) information of a target base station (13) for admitted service flows during a handover operation. The invention comprises providing a service to a mobile station (11) from a serving base station (12) and receiving at the serving base station (12) a handover request (S107) from the mobile station (11). The serving base station (12) then provides a handover notification (S108) to a target base station (13), wherein the handover notification comprises a QoS parameter associated with the service. The serving base station (12) then receives from the target base station (13) a handover notification response (S109), wherein the handover notification response comprises service level prediction information that is determined in response to the QoS parameter associated with the service. Finally, the serving base station (12) provides a handover response (S110) to the mobile station (11), the handover response comprising the service level prediction information.

Abstract: A method for supporting handover in a BWA communication system is provided. The system includes an MS, a serving BS, and a plurality of neighbor BSs. The coverage area of each of the BSs is divided into sectors using different subcarrier bands. The MS collects information broadcast from the serving BS on the serving BS and the neighbor BS, measures a signal level for each of the sectors of the serving BS and the neighbor BSs according to the collected information, and sends a handover request based on the measured signal level for each of the sectors. The serving BS broadcasts information on the serving BS and the neighbor BS to the MS, determines if the MS can perform a soft handover from its current sector to another sector upon receiving the handover request from the MS, and permits the MS to perform the soft handover if possible.

Abstract: In order to improve the accuracy of the vertical handoff decision for radio heterogeneous network, this paper proposes an adaptive multi-criteria vertical handoff (AMVHO) decision algorithm. This algorithm uses a fuzzy inference system (FIS) and a modified Elman neural network (MENN). The FIS adopts crucial criteria of the vertical handoff as the input variables and makes handoff decision based on the defined rule base. The MENN helps to do the prediction for number-of-users of the after-handoff network, which is a pivotal variable of the FIS. Simulation results show that compared with the conventional method, the AMVHO decision algorithm achieves better performance in guaranteeing the quality of service (QoS) of the after-handoff communication.

Abstract: Various embodiments are described to address the need for reduced handoff delays associated with inter-AN (access network) HRPD (High Rate Packet Data)/1XEV-DO handoffs. The disclosed approach enables an AT (101) with an active packet data session to perform a hard handoff from a source AN (121, 221) to a target AN (122, 222) without having to force the data session dormant. Unlike known hard handoff approaches that involve coordination by a mobile switching center (MSC), the disclosed approach uses peer-to-peer signaling with no MSC involvement, such as that between source and target ANs or PCFs (131, 132, 231, 232). For example, data session information at the source side is transferred via new A13 messaging to the source entity's target-side peer to otherwise reduce signaling between the source and target equipment.

Abstract: To enable seamless IP-layer handover of a mobile node (MN) from one access router (AR) to another, the MN is required to discover the identities and capabilities of candidate ARs (CARs) for handover prior to the initiation of the handover. The act of discovery of CARs has two aspects: identifying the IP addresses of the CARs and finding their capabilities. This process is called "candidate access router discovery" (CARD). At the time of IP-layer handover, the CAR, whose capabilities are a good match to the preferences of the MN, is chosen as the target AR for handover. The protocol described in this document allows a mobile node to perform CARD. This memo defines an Experimental Protocol for the Internet community.

Abstract: As the working hours of junior doctors decrease, adequate handover of patients becomes more important to maintain continuity of care and avoid errors caused by information gaps. A minimum dataset for surgical handover should include the patient's name, location (ward and bed number), date of admission, diagnosis, procedure (with date), complications and progress, management plan, resuscitation plan, consultant availability (and instructions if not available), expected need for review, and name of doctor completing handover and date to confirm that information is current. An electronic handover system is a potential solution, but our survey shows that free-text entry into such systems may be inadequate; prompts or predefined fields for handover content are possible solutions.

Abstract: Recently, user mobility in wireless data networks is increasing because of the popularity of portable devices and the desire for voice and multimedia applications. These applications, however, require fast handoffs among base stations to maintain the quality of the connections. Re-authentication during handoff procedures causes a long handoff latency which affects the flow and service quality especially for multimedia applications. Therefore minimizing re-authentication latency is crucial in order to support real-time multimedia applications on public wireless IP networks.In this paper, we proposed two fast re-authentication methods based on the predictive authentication mechanism defined by IEEE 802.11i security group. We have implemented these methods in an experimental test-bed using freeware and commodity 802.11 hardware and we demonstrate that they provide significant latency reductions compared to already proposed solutions. Conducted measurements show a very low latency not exceeding 50 ms under extreme congested network conditions.

Abstract: As mobile wireless networks increase in popularity and pervasiveness, we are facing the challenge of integration of diverse wireless networks such as WLANs and WWANs. Consequently, it is becoming progressively more important to arrive at a vertical handoff solution where users can move among various types of networks efficiently and seamlessly. The ability to remain connected as a mobile device roams across different types of networks still remains an unachieved objective. Frequently, just choosing the best network to connect to, is a challenging problem due to the large number of network characteristics that need to be considered. Identifying these decision factors is therefore one of the principal objectives for seamless mobility. In this paper, we discuss the different factors and metric qualities that give an indication of whether or not a handoff is needed. We then describe a vertical handoff decision function, VHDF, which enables devices to assign weights to different network factors such as monetary cost, quality of service, power requirements, personal preference, etc.

Abstract: While handover management has traditionally used radio-technology-specific mechanisms, the need for integration of this diverse network environment has obviated the "push" of the handover functionality to the generic IP layer that serves the rendezvous point of underlying technologies. In this context, we study and analyze the implications of the link-layer agnostic operation of IP handover control on handover performance, having as a reference the fast mobile IPv6 protocol. We show that the behavior of the protocol (i.e., whether a reactive or proactive operation will be executed) is highly dependent on the timely availability of link layer information. A non-exhaustive list of generic link-layer triggers used for this purpose, as identified by the IEEE 802.21 WG, is also presented. Last, we apply this generic framework to a WLAN environment running fast mobile IPv6 and study the improvements in fast handoff support.

Abstract: A satellite communications system includes a satellite that is configured to wirelessly communicate with radioterminals in a satellite coverage area over a satellite frequency band, and an ancillary terrestrial component that is configured to wirelessly communicate with radioterminals in the satellite coverage area over at least some of the satellite frequency band, to thereby terrestrially reuse at least some of the satellite frequency band. Wireless communications with a radioterminal are handed over from the ancillary terrestrial component to the satellite if the radioterminal transmit power exceeds a threshold, and a received satellite signal quality exceeds a threshold, even though the radioterminal is able to wirelessly communicate with the ancillary terrestrial component. Downlink wireless radiation that is received at the radioterminal from a satellite may be monitored to determine potential interference created by the uplink radiation of the radioterminal due to the terrestrial reuse of at least some of the satellite frequency band.

Abstract: Disclosed is a method for recognizing by a Mobile Subscriber Station (MSS) whether a serving Base Station (BS) retains connection information in a mobile communication system including the serving BS for providing a service to the MSS and a target BS adjacent to the serving BS. The method includes the steps of receiving a handover request message from the serving BS, the handover request message including a resource remain type field representing whether the connection information having been set with the serving BS is retained, and a resource retain time field representing a connection information-retaining time by the serving BS, and recognizing that the serving BS retains the connection information during a time determined by a value of the resource retain time field.

Abstract: The present invention facilitates handoffs for a mobile terminal in a wireless access network that is capable of supporting different types of handoffs. The different handoff types may include soft handoffs and fast base station switching (FBSS). In operation, context information associated with supporting wireless communications between the wireless access network and the mobile terminal are determined. Based on whether the context information is shared between base stations involved in the handoff or transferred from one base station to another of the base stations involved in the handoff, a particular handoff type is selected from the different handoff types that are available. Selecting the specific type of handoff to use may also be based on the level of context information that is available, the actual content of the context information, application preferences, channel conditions, base station or mobile terminal capabilities, or any combination thereof.