Abstract:
A communications system provides a robust and fast inter-base station handoff mechanism, e.g. for networks using Enhanced Base Stations (EBS) equipment. A method for connecting a mobile device to a destination base station in the wireless communications system, may include steps of receiving a mobile device measurement report, transferring context information from a serving base station to possible target base stations, and receiving admission control information from possible target base stations. A priority list of the possible target base stations is calculated and sent to the mobile device. The mobile device connects to one or more of possible target base stations according to the priority list. The method may also entail receiving a release message from one of the possible target base stations to which the mobile device has successfully established a wireless connection, to allow release of resources of the prior serving base station.

Description:
TECHNICAL FIELD 
       [0001]    The subject matter discussed herein relates to techniques and equipment to ensure a more efficient, fast and robust handoff in wireless communications. 
       BACKGROUND 
       [0002]    In recent years, many mobile service providers have been upgrading wireless networks to support packet-switched data communications services, which extend the common data communication capabilities of the wired domain to the wireless mobile domain. A popular advantage of wireless communications is the freedom of mobility. To support mobile communication, the wireless networks perform a function called “handoff” or “handover”. Handoff is the process by which elements of a mobile network pass a cellular phone conversation or data session from one radio channel in one cell to another radio channel in another cell. It is performed so quickly that callers do not notice. Handoff, unlike roaming, involves moving an active call from one radio to another radio. Roaming involves registering for service/access through different locations on various regional networks, as a mobile station user moves. 
         [0003]    In Code Division Multiple Access (CDMA) cellular telecommunication systems, a handoff is usually accomplished via a “soft handoff” between sectors or from one base station to another base station. In a soft handoff between base stations, for example, the mobile station is in communication with more than one base station simultaneously, and thus the mobile station performs a “make before break” transition from one base station to another base station. The soft handoff is possible because in CDMA cellular telecommunication systems, numerous mobile stations communicate with each base station on the same frequency channel, each mobile station having a unique spreading code or offset thereof for distinguishing the information signals broadcast by the numerous mobile stations. Thus, when a mobile station moves from one CDMA cell to another CDMA cell, the same frequency is used in each CDMA cell and the unique spreading code identifies the mobile station to the new base station. 
         [0004]    A “hard handoff” occurs when it becomes necessary to handoff between systems, e.g. between systems of different service providers or between systems using different technologies (e.g. between CDMA and Advanced Mobile Phone System (AMPS), Time Division Multiple Access (TDMA) or Global System for Mobile communications (GSM) systems). The hard handoff is a “break before make” connection. The hard handoff may be necessary because the available frequency channels or the encoding technologies used in the two adjoining systems differ, and thus when a mobile station moves from one to another, a new frequency channel or coding technique must be implemented. 
         [0005]    However, next generation radio access networks are moving away from “soft handoff” in order to more efficiently utilize radio resources. The Next Generation Network (NGN) will be dominated by asynchronous radio access networks providing only hard handoff. This makes fast and robust handoff across various radio access points extremely important. 
         [0006]    Furthermore, current inter-Enhanced Base Station (EBS) handoff in Long Term Evolution (LTE) and inter-Access Point (AP) handoff in Worldwide Interoperability for Microwave Access (WiMAX) only defines and prepares one potential Target EBS. However, for example, when only one potential Target EBS is prepared, latency in handoff can result. In LTE and WiMAX, when a handoff is prepared, only one potential Target EBS is prepared for the handoff. Afterwards, if a signal interruption results between the Target EBS and the mobile station such that the mobile station cannot connect to the Target EBS, then the mobile station will remain connected to the Serving EBS. However, since only one potential Target EBS was prepared, then the Serving EBS will have to prepare another Target EBS for a handoff. This preparation takes time and results in the mobile station remaining connected to the Serving EBS longer than needed. This further consumes system resources. This results in system latency and poor handoff performance. However, the current LTE and WiMAX approaches result in poor handoff performance. 
         [0007]    Additionally, Ultra Mobile Broadband (UMB) is a synchronized network which stores dual radio stacks at both Serving and Target EBS, which results in complicated terminal equipment. 
         [0008]    Hence a need exists for a means to more efficiently determine and transfer call context information to multiple EBSs to ensure a fast and robust handoff mechanism that minimizes latency, handoff interruption and outage performance without actively involving multiple EBSs. 
       SUMMARY 
       [0009]    The teachings herein alleviate one or more of the above noted problems with latency in handoff. 
         [0010]    A data communication system software and method are disclosed herein, which incorporate concepts to address the above noted problems with handoff between base stations during an active wireless communication session. 
         [0011]    For example, a method and/or a communication system software provide a mechanism for a network entity to prepare and direct the subscriber to Target EBSs to support a robust and fast handoff. 
         [0012]    A method for connecting a mobile device to a destination base station in a wireless communications system, comprising steps of receiving a mobile device measurement report, wherein the measurement report includes at least a plurality of possible target base stations and a plurality of signal strengths of possible target base stations measured by the mobile device, transferring context information from a serving base station to the plurality of possible target base stations, wherein the context information includes at least a mobile device identification and a transfer request, receiving admission control information from the plurality of possible target base stations, forming a ranking matrix of parameters with respect to the plurality of possible target base stations, calculating a ranking value of the plurality of possible target base stations based upon the parameters in the matrix, calculating a priority list of the plurality of possible target base stations according to their respective ranking values, sending the priority list to the mobile device, commanding the mobile device to select and attempt to connect to at least one of the plurality of possible target base stations, according to the priority list; and receiving a release message from one of the plurality of possible target base stations to which the mobile device has successfully established a wireless connection, wherein the release message allows for releasing resources of the serving base station dedicated to the serving mobile device. Furthermore, the parameters include at least a neighbor listing of the plurality of possible target base stations, and the signal strengths from the mobile device measurement report. 
         [0013]    The methodology may be implemented in any wireless network offering packet data communication services. Specific processing examples are discussed below for implementation in a 4G type wireless access network and for implementation in an Evolution Data Only (EVDO) type wireless network. 
         [0014]    The exemplary methodology provides a mechanism for supporting a robust and fast inter-EBS handoff mechanism within 4G radio access networks. The methodology supports context transfer between a serving radio access point EBS and multiple target EBSs, and updates an intelligent neighbor data base at a network entity to enable fast and robust handoff when a mobile subscriber moves from one EBS to another EBS in an asynchronous network. 
         [0015]    Hence, the wireless technologies discussed herein provide handoff control in accord with an intelligent EBS database and use the same version of software for all EBSs. An advantage provided by the disclosed approach is that the mobile device will not go through an idle-to-active transition when being handed off to another EBS. Furthermore, the Target EBS will be ready for the handoff of Mobile Device  102 . The invention also proposes a method and procedure to recover the subscriber from handoff failure. 
         [0016]    Additional advantages and novel features will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by production or operation of the examples. The advantages of the present teachings may be realized and attained by practice or use of various aspects of the methodologies, instrumentalities and combinations set forth in the detailed examples discussed below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements. 
           [0018]      FIG. 1  is an exemplary wireless network for providing high speed voice and data services. 
           [0019]      FIG. 2  is an exemplary block diagram of an EBS that implements the handoff mechanism of the present disclosure. 
           [0020]      FIG. 3  is a signal flow diagram of the prior art handoff mechanism used in an EBS. 
           [0021]      FIG. 4   a  is a signal flow diagram of the present disclosure used in an EBS. 
           [0022]      FIG. 4   b  is an exemplary block diagram of a ranking matrix that is utilized in one embodiment of the present disclosure. 
           [0023]      FIG. 5  is a signal flow diagram of the present disclosure when a radio link failure occurs after handoff preparation, but prior to the mobile device receiving a priority list. 
           [0024]      FIG. 6  is a signal flow diagram of the present disclosure when a radio link failure occurs after the mobile device receives the priority list. 
           [0025]      FIG. 7  is a signal flow diagram of the present disclosure when a radio link failure occurs before handoff preparation. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings. 
         [0027]    Reference now is made in detail to the examples illustrated in the accompanying drawings and discussed below.  FIG. 1  illustrates a functional block diagram of an exemplary wireless network  100  for providing high speed voice and data services, which may implement handoff in accord with the present concepts. The illustrated network  100 , for example, involves 4G radio access networks and technology that enables a Mobile Device  102  to access the Network  130  and/or the Internet  140  over the air via a Serving EBS  104 . 
         [0028]    In  FIG. 1 , Mobile Device  102  can connect to any of the EBSs (Serving EBS  104 , Target EBS 1   108  and Target EBS 2   110 ) in order to make a call (i.e. voice) or to transfer/receive data. Serving EBS  104 , Target EBS 1   108  and/or Target EBS 2   110  provide wireless access points to Mobility Management Entity/System Architecture Evolution GateWay (MME/SAE GW)  120 , Network  130  and Internet  140 . In  FIG. 1 , Mobile Device  102  is connected to Serving EBS  104  via the air. Serving EBS  104  is connected to Network  130  and Internet  140  via MME/SAE GW  120 . As a result, Mobile Device  102  can complete a call (i.e. voice) with other devices connected to Network  130  and/or Internet  140 . Furthermore, Mobile Device  102  can transfer/receive data to any other devices attached to Network  130  and/or Internet  140 . Target EBS 1   108  and Target EBS 2   110  are alternative cellular communications towers that are connected to MME/SAE GW  120 , Network  130  and Internet  140 . Therefore, Mobile Device  102  also can connect to MME/SAE GW  120  via use of Target EBS 1   108  and Target EBS 2   110 . In  FIG. 1 , if it is more feasible for Mobile Device  102  to be connected to a different EBS (Target EBS 1   108  and Target EBS 2   110 ), then a handoff may result. This may occur for a number of different reasons, for example, Mobile Device  102  may have repositioned itself to be located in a position closer to a different EBS, the Serving EBS  104  may be supporting a number of other mobile devices resulting in congestion at Serving EBS  104 . Regardless of the reason for the handoff, Serving EBS  104  will communicate with alternative EBSs (Target EBS 1   108  and Target EBS 2   110 ) via interfaces between EBSs (dashed lines in  FIG. 1 ) and/or MME/SAE GW  120 . The alternative EBSs (Target EBS 1   108  and Target EBS 2   110 ) will update the Serving EBS  104  of their ability to support Mobile Device  102  and also include other information that Serving EBS  104  may utilize in order to make a handoff decision. Once a handoff decision has been made by Serving EBS  104 , then Serving EBS  104  will coordinate with Mobile Device  102  and the alternative EBSs to ensure a connection can be made between Mobile Device  102  and the alternative EBSs. Once the handoff connection is completed, then the Serving EBS  104  will be released from its connection with Mobile Device  102  and the new Serving EBS will coordinate with MME/SAE GW  120  the reallocation of system resources from the handoff. 
         [0029]      FIG. 2  is a functional block diagram of an exemplary EBS  104  for providing high speed data services over the air, which implements handoff in accord with the present concepts. The illustrated EBS  104 , for example, involves 4G radio access networks and technology. Furthermore, while this exemplary embodiment provides the details on the inner-workings of the Serving EBS  104 , it is understood that each EBS in the wireless network  100  incorporates elements similar to or the same as those shown in the functional block diagram of Serving EBS  104  shown in  FIG. 2 . 
         [0030]    The Serving EBS  104  receives and transmits RF signals via Antennas  225  and  223 . The RF signals are processed by Transmitter (Tx)/Receiver (Rx) elements  219  and  221 . Tx/Rx elements  219  and  221  perform signal analysis and processing including upconverting/downconverting of the data signal, amplification, filtering, etc. 
         [0031]    Layer 1/Layer 2 Processor  217  (L1/L2 Processor  217 ) performs multiplexing/de-multiplexing upper layer packets onto/from physical channels. L1/L2 Processor  217  includes Physical Layer processing (PHY), Media Access Control (MAC) and Radio Link Control (RLC). The RLC is responsible for the segmentation of IP packets, retransmission of erroneously received packets, and in-sequence delivery of packets to upper layers. The MAC layer provides addressing and channel access control mechanisms. 
         [0032]    Handover Control  211  controls the mechanics of the actual handoff process. Handover Control  211  communicates with the other units contained within Serving EBS  104  to ensure that the handoff process is performed correctly. Therefore, various signaling parameters are involved. The signaling performed in the embodiments discussed in  FIGS. 4-7  and certain aspects of the Ranking Matrix  463  are performed by Handoff Control  211 . Handoff Control  211  interacts with an Intelligent EBS Database  459  (discussed below) in order to properly control the handoff. The Intelligent EBS Database  459  contains information on all of the neighboring cell sites (EBSs) in the wireless network  100 . The control path functions are performed by Intelligent EBS Database  459 , Handover Control  211 , and Radio Resource Mgmt  215 . Radio Resource Mgmt  215  performs Radio Bearer Control, Radio Admission Control, and the dynamic allocation of resources to Mobile Devices bi-directionally. Radio Resource Mgmt  215  may also include the Handover Control  211  functions. 
         [0033]    Ciphering Robust Header Compression (ROHC)  213  performs encryption/decryption and Robust Header Compression. Furthermore, Ciphering ROHC  213  may also compress packets received from the MME/SAE GW  120  and forward the compressed data to L1/L2 Processor  217 . Ciphering ROHC  213  is performed in order to compress Internet Protocol (IP), User Datagram Protocol (UDP), Real-time Transport Protocol (RTP), and Transmission Control Protocol (TCP) headers of internet packets destined for downstream transmission over the air to mobile devices served by the Serving EBS  104 . ROHC performs well over wireless communications links where the packet loss rate may be high. Encryption/decryption is performed in order to ensure security of the transmitted/received data. The packet data from SAE GW (shown as dashed line/“Signaling Traffic” in  FIG. 2 ) is ciphered and compressed at Ciphering ROHC  213  and transmitted to L1/L2 Processor  217 . The control data (shown as solid line/“Bearer Traffic” in  FIG. 2 ) bypasses Ciphering ROHC  213  and is directly connected to L1/L2 Processor  217 . 
         [0034]    To appreciate the improvement(s) provided by the present implementation of the handoff process, it may be helpful first to consider a typical process for transferring a communications session from one EBS to another EBS without the present enhancements. For that purpose,  FIG. 3  is an exemplary call flow diagram for the prior art, when a Mobile Device  102  is connected to a Serving EBS  104  and the Mobile Device  102  is handed off to a Target EBS  106 . Prior to the handoff, Mobile Device  102  is connected to the Serving EBS  104  and is capable of transferring Packet Data  301   a  and  301   b  to and/or from the rest of the network (MME/SAE GW  120  and Network  130 ) via the Serving EBS  104 . 
         [0035]    The Serving EBS  104  configures the Mobile Device Measurement Control Procedures  305  in order to obtain a measurement report  309  from the Mobile Device  102 . Hence, in the example the Mobile Device  102  receives the measurement control procedures and command at  305  from the Serving EBS  104  and subsequently sends a measurement report  309  of the surrounding EBS signal strengths, as measured by the Mobile Device  102 , to the Serving EBS  104 . The measurement report  309  can be sent either perodically or by a triggered event that is configured by the network. In one embodiment, the measurement report  309  is a Radio Frequency (RF) signal strength measurement as measured by Mobile Device  102 . 
         [0036]    Upon receiving the measurement report  309 , the Serving EBS  104  makes a Handoff Decision  313  to handoff the Mobile Device  102  to another EBS. For this purpose, the Serving EBS  104  determines the Target EBS  106  based on the measurement report  309  and other EBS&#39;s loading conditions, the previous HO statistics, etc. Afterwards, the Serving EBS  104  sends a Handoff Request  317  to the one identified Target EBS  206 . The Handoff Request  317  contains context information of the Mobile Device  102 . However, if the Target EBS  106  does not receive the Handoff Request  317 , then no handoff will occur. Furthermore, an idle to active transition can occur, which results in handoff preparation latency. 
         [0037]    The Target EBS  106  performs Admission Control  321  in order to gauge available network resources and sends a Handoff Request Acknowlegement  325  back to the Serving EBS  104  (assuming network resources are available). Furthermore, the Target EBS  106  stores the Mobile Device  102  context information and reserves Layer 1/Layer 2 (L1/L2) resources in order to assist with the handoff. In one exemplary embodiment, the L1/L2 resources include a Cell Radio Network Temporary Identifier (CRNTI). 
         [0038]    The Serving EBS  104  receives the Handoff Request Acknowlegement  325  from the Target EBS  106 , and subsequently directs the Mobile Device  102  to handoff to the Target EBS  206  via a Handoff Command message  329 . 
         [0039]    The Mobile Device  102  receives the Handoff Command message  329  from the Serving EBS  104 , and the Mobile Device  102  synchronizes with the Target EBS  106  via Sync+Timing Advance UL Allocation message  333 . Sync+Timing Advance UL Allocation message  333  also allows the Target EBS  206  to assign an uplink allocation and a timing advance to the Mobile Device  102 . 
         [0040]    Afterwards, the Mobile Device  102  sends a Handoff Confirm message  337  to the Target EBS  106  to indicate the completion of the handoff procedure. 
         [0041]    The Target EBS  106  performs a Path Switch Procedure  341  to update the MME/SAE GW  120  of the handoff. After the Path Switch Procedure  341  is completed, the Target EBS  206  sends a Resource Release Message  345  to the Serving EBS  104  to trigger the release of the system resources previously used by the Mobile Device  102  at the Serving EBS  104 . 
         [0042]    As a result of the handoff, Mobile Device  102  is connected to the Target EBS  106 ; and packet data is transferred with MME/SAE GW  120  via Packet Data messages  349  and  351 . 
         [0043]    To appreciate the operation of the network and an exemplary implementation of the present handoff process, it may be helpful next to consider an exemplary process for transferring a communications session from an EBS to another EBS. For that purpose,  FIG. 4   a  is an exemplary handoff call flow for an exemplary implementation of the new process. Specifically,  FIG. 4   a  illustrates a call flow diagram, when a Mobile Device  102  is connected to a Serving EBS  104  and the Mobile Device  102  is to be handed off to a Target EBS. Prior to the handoff, Mobile Device  102  is connected to the Serving EBS  104  and is capable of transferring Packet Data  401   a  and  401   b  to the rest of the network (MME/SAE GW  120 ) via the Serving EBS  104 . 
         [0044]    The Serving EBS  104  configures the handset measurement control procedures at  405  in order to obtain a measurement report  409  from the Mobile Device  102 . Hence, in the example, the Mobile Device  102  receives the measurement control procedures and command at  405  from the Serving EBS  104  and subsequently sends a measurement report  409  of the surrounding EBS signal strengths, as measured by the Mobile Device  102 , to the Serving EBS  104 . The measurement report  409  can be sent either perodically or by a triggered event that is configured by the network  100 . In one embodiment, the measurement report  409  is a RF signal strength measurement as measured by Mobile Device  102 . 
         [0045]    Upon receiving the measurement report  409 , the Serving EBS  104  makes a handoff decision  413  to handoff the Mobile Device  102  to another EBS. However, in the procedure of  FIG. 4   a , the Serving EBS  104  does not know at this instant in time, which EBS the Mobile Device  102  will be transferred to. The ultimate handoff destination will be determined from among Target EBS 1 , EBS 2 , . . . , or EBSn, based on a Ranking Matrix  463  (discussed below). While this illustrated example shows two target EBSs, for simplicity, it is understood that there could possibly be N Target EBSs. 
         [0046]    Hence, in the example, the Serving EBS  104  sends a handoff request  417  to each potential Target EBS, that is to say to Target EBS 1   108  and Target EBS 2   110  in  FIG. 4   a . The handoff request  417  contains context information of the Mobile Device  102 . 
         [0047]    Target EBS 1   108  and Target EBS 2   110  perform admission control  421  in order to gauge the available network resources. Furthermore, each Target EBS 1   108  and Target EBS 2   110  sends a handoff request acknowlegement  425  to the Serving EBS  104 . 
         [0048]    Additionally, both Target EBS 1   108  and Target EBS 2   110  store the Mobile Device  102  context information and reserve Layer 1/Layer 2 (L1/L2) resources in order to assist with the handoff. In one exemplary embodiment, the L1/L2 resources are CRNTI or optional random access channel preamble, as well as the required radio resources to satisfy the QoS of Mobile Device  102 &#39;s radio bearers. The L1/L2 resources will be released after a time-out to be utilized for other purposes. 
         [0049]    The Serving EBS  104  receives handoff request acknowlegements  425  from both Target EBS 1   108  and Target EBS 2   110 . Afterwards, the Serving EBS  104  generates a Priority List  427 . 
         [0050]    The Priority List  427  provides a ranking of the available neighboring EBSs and is based on information such as cell size, carrier frequency, site location, capacity or loading, available services, signal strengths, etc. Furthermore, the Priority List  427  also contains stored information of neighboring EBSs&#39; loading condition, Handset Measurement Report  409  and data application and service quality available at the neighboring EBSs. The Priority List  427  is generated based on the ranking matrix. Table 1 below shows an example of a ranking matrix, and examples of the Priority List  427  are illustrated in Tables 2 and 3 (discussed below). 
         [0051]    The Serving EBS  104  directs the Mobile Device  102 , via a Handoff Command Message  429 , to handoff to a Target EBS (in this embodiment EBS 1   108 ). The Handoff Command Message  429  will contain either the whole Priority List  427  or the top-ranked Target EBSs from the Priority List  427 . 
         [0052]    The Mobile Device  102  receives the Handoff Command message  429  from the Serving EBS  104  with the Priority List  427  and begins contacting potential Target EBSs based on the Priority List  427 . In the example of  FIG. 4   a , we will assume that Target EBS 1   108  ranks highest on the Priority List  427 . Hence, the Handset synchronizes with the Target EBS 1   108  via Sync+Timing Advance UL Allocation message  433 . Sync+Timing Advance UL Allocation message  433  also allows the Target EBS 1   108  to assign an uplink allocation and a timing advance to the Mobile Device  102 . 
         [0053]    Afterwards, the Mobile Device  102  sends a handoff confirm message  437  to the Target EBS  108  to indicate the completion of the handoff procedure. 
         [0054]    The Target EBS 1   108  performs a Path Switch Procedure  441  to update the MME/SAE GW  120  of the handoff. After the Path Switch Procedure  441  is completed, the Target EBS 1   108  sends a Resource Release Message  445  to the Serving EBS  104  to trigger the release of the system resources previously used by the Mobile Device  102  at the Serving EBS  104 . 
         [0055]    As a result of the handoff, Mobile Device  102  is connected to the Target EBS 1   108  and packet data is transferred with MME/SAE GW  120  via Packet Data messages  449  and  451 . However, if for some reason Mobile Device  102  cannot connect to Target EBS 1  prior to handoff, then Mobile Device  102  may connect to any of the other available Target EBSs based upon the Priority List  427 . Therefore, Mobile Device  102  does not need to wait to be assigned a new Target EBS resulting in handoff preparation latency. 
         [0056]    To appreciate the operation of the network and implementation of the handoff process, it may be helpful next to consider an exemplary process for generating a Ranking Matrix  463 , after which we will discuss deriving a Priority List  427  from such a matrix. For that purpose,  FIG. 4   b  is a process flow for generating an exemplary Ranking Mechanism utilized in the handoff system.  FIG. 4   b  illustrates several examples of parameters that are utilized by the Ranking Matrix  463  in the determination of the Priority List  427 . 
         [0057]    The Serving EBS  104  will generate the Ranking Matrix  463  based upon a number of variables. In this exemplary embodiment, the Ranking Matrix  463  is generated according to a Neighbor List  458 , a Loading Factor  456 , User Radio Measurements  460  and an Achievable Service Quality  455  of each of the potential Target EBSs. The Ranking Matrix  463  ranks each of the above-mentioned, individual parameters based upon an index for each potential Target EBS. Table 1 (shown below) illustrates an example of a Ranking Matrix. Furthermore, the Serving EBS  104  contains an Intelligent EBS Database  459  that contains all of the neighboring cell sites (Target EBSs) in a Neighbor List  458 . The Intelligent EBS Database  459  is updated every time a handoff is made. 
         [0058]    At  453 , the Serving EBS  104  will determine what current Applications and Service Quality are utilized by the Mobile Device  102 . 
         [0059]    At  454 , the Serving EBS  104  will determine if the current Applications and Service Quality of the Mobile Device  102  are supported by the current Target EBSs via use of the Intelligent EBS Database  459 . It is noted that only wireless communication cells that are capable of supporting the current Applications and Achievable Service Quality  453  of the Mobile Device  102  will be included in the Ranking Matrix  463 . This ensures efficiency in the handoff preparation process and reduces latency in the system. In one exemplary embodiment, the Applications and Service Quality  453  may be various IP packet applications and IP service quality requirements such as TCP/IP. If yes at  454 , then processing branches to  456 . 
         [0060]    At  455 , the Serving EBS  104  compiles an index of potential Target EBSs that support the current applications and achievable service quality of the Mobile Device  102 . For example, if a particular Target EBS can provide more service quality, then the more influence this parameter will have in the Application/Service Quality rank index. Afterwards, processing for this branch proceeds to  463 . 
         [0061]    At  456 , the Serving EBS  104  determines the Loading Factor  456  of the Target EBSs via use of the Intelligent EBS Database  459 . The Loading Factor  456  is the current network loading condition of each Target EBS (that supports the current Handset Applications—discussed above). 
         [0062]    At  457 , the Serving EBS  104  examines the Loading Factor  456  to determine if the Loading Factor  456  exceeds a Threshold  457 ; the Target EBSs with a Loading Factor  456  exceeding the Threshold  457  will be excluded from the Ranking Matrix  463 . This helps to ensure that the congested Target EBSs are not overwhelmed unnecessarily with congestion by distributing the network load across other viable Target EBSs. Therefore, the Target EBSs with an acceptable Loading Factor  456  will be included in the Ranking Matrix  463 . 
         [0063]    At  458 , the Serving EBS  104  determines the Neighbor List  458 , which is a listing of all available neighboring cell sites, i.e. Target EBSs. The Neighbor List  458  is contained within the Intelligent EBS Database  459 . The Neighbor List  458  can be adjusted based upon the proximity of the Target EBSs to the Serving EBS  104 . Furthermore, the Neighbor List  458  is updated based upon how frequently the Mobile Device  102  is handed over from the Serving EBS  104 . For example, if a Mobile Device  102  is handed over to a potential Target EBS from the Serving EBS  104 , then the Neighbor List rank index of that particular EBS will be updated in the Serving EBS&#39;  104  Intelligent Database  459 . 
         [0064]    At  459 , the Serving EBS  104  will view the Neighbor List  458  via use of the Intelligent EBS Database  459 . 
         [0065]    At  460 , the Serving EBS  104  will determine the User Radio Measurements  460  of Mobile Device  102 . The User Radio Measurements  460  are the strength of the received RF-signal, measured by the Mobile Device  102  and from Target EBSs in the vicinity. This ensures that multi-path and various other propagation issues are accounted for. For example, if the RF signal of a potential Target EBS is stronger than other potential Target EBSs, then the more influence this parameter will have in the RF-Strength rank index. Also, some neighboring EBSs may not be detected at an adequate level by the Mobile Device  102 , e.g. due to an obstruction. 
         [0066]    At  463 , the Serving EBS  104  generates the Ranking Matrix  463 . The Ranking Matrix  463  weights the Neighbor List  467 , the Loading Factor  459 , User Radio Measurements  471  and the Achievable Service Quality  473 , for each of the potential Target EBSs based upon an index. Table 1 illustrates an example of such a Ranking Matrix. In the example of Ranking Matrix  463 , a Final Target EBS ranking is calculated by multiplying the above four rank indices of all potential Target EBSs with a set of pre-defined weighting factors. The values of the weighting factors are based on the network deployment scenario established by a service operator on a per sector basis. For example, the weighting factors for a Macro-cellular network and Urban Canyon network will be different. The Macro-cellular network scenario may emphasize the User Radio Measurements  460 , whereas the Urban Canyon network scenario may emphasize the Neighbor List  458  as illustrated in Table 1. Afterwards, the Final Target EBS ranking entries will be ranked according to whether the Urban-Canyon or Macro-Cell scenario is employed. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Ranking Matrix 
               
             
          
           
               
                   
                   
                   
                 Application - 
                   
                   
                   
               
               
                   
                   
                 RF 
                 Service 
                   
                 
                   Urban- 
                 
                 
                   Macro- 
                 
               
               
                 Target 
                 Neighbor 
                 Strength 
                 Quality 
                 Loading 
                 
                   Canyon 
                 
                 
                   Cell 
                 
               
               
                   
               
               
                 EBS1 
                 1 
                 2 
                 4 
                 3 
                 
                   1.7 
                 
                 2.1 
               
               
                 EBS2 
                 2 
                 1 
                 1 
                 4 
                 1.9 
                 
                   1.5 
                 
               
               
                 EBS3 
                 3 
                 4 
                 2 
                 1 
                 2.9 
                 3.3 
               
               
                 EBS4 
                 4 
                 3 
                 3 
                 2 
                 3.5 
                 3.1 
               
               
                   
               
             
          
         
       
     
         [0067]    In the example provided by Table 1, the Urban Canyon scenario uses the following weighting factors: 6/10 weighing to the Neighbor List  458 , 2/10 weighting to the User Radio Measurements  460 , 1/10 weighting to the Achievable Service Quality  455  and 1/10 weighting to the Loading Factor  456 . In this exemplary embodiment, the Target EBS with the lowest Neighbor rank index is Target EBS 1  (the lowest score is the best potential handoff candidate). In other words, Target EBS 1  is ranked first out of the four possible EBSs for the Neighbor rank index. This reflects the fact that, in this example, the Urban Canyon network scenario emphasizes the Neighbor List  458  index by multiplying the index by a 6/10 weighting factor. Therefore, even though the Achievable Service Quality  455  index of EBS 1  is ranked fourth out of the four possible EBSs, this particular index is de-emphasized in this Urban Canyon network scenario by being multiplied by a 1/10 weighting factor. 
         [0068]    At  427 , the serving EBS  104  generates the Priority List  427  from the Ranking Matrix  463  illustrated in Table 1. The Priority List  427  may be a whole or partial copy of the information contained in the Ranking Matrix  463 . In this example, for ease of illustration, the Priority List  427  contains the same entries as the Ranking Matrix  463 . However, it is understood that in an actual implementation, the Priority List  427  may be parsed down as shown in Tables 4, 5 and 6. Table 2 illustrates an example of the Priority List  427  for the Urban-Canyon scenario. It is noted that Ranking Matrix  463  has been re-ranked according to the Urban-Canyon matrix entries (not shown). As illustrated in Table 2, Target EBS 1  has the lowest accumulated score in the Urban-Canyon field. Therefore, Mobile Device  102  would first attempt to handoff to Target EBS 1 . If for some reason Mobile Device  102  could not handoff to Target EBS 1 , then Mobile Device  102  would attempt the next entry in the Priority List  427 . In this example, Mobile Device  102  would attempt to handoff to Target EBS 2  since that is the next available Target EBS in the Urban-Canyon list. If Mobile Device  102  could not handoff to Target EBS 2 , then Mobile Device  102  would attempt to handoff to Target EBS 3  and Target EBS 4 , in order. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Priority List Ranked According to Urban-Canyon Scenario 
               
             
          
           
               
                   
                   
                   
                 Application - 
                   
                 
                   Urban- 
                 
                 Macro- 
               
               
                   
                 Geo- 
                 RF 
                 Service 
                   
                 
                   Canyon 
                 
                 Cell 
               
               
                 Target 
                 Neighbor 
                 Strength 
                 Quality 
                 Loading 
                 
                   Ranking 
                 
                 Ranking 
               
               
                   
               
               
                 EBS1 
                 1 
                 2 
                 4 
                 3 
                 
                   1.7 
                 
                 2.1 
               
               
                 EBS2 
                 2 
                 1 
                 1 
                 4 
                 1.9 
                 
                   1.5 
                 
               
               
                 EBS3 
                 3 
                 4 
                 2 
                 1 
                 2.9 
                 3.3 
               
               
                 EBS4 
                 4 
                 3 
                 3 
                 2 
                 3.5 
                 3.1 
               
               
                   
               
             
          
         
       
     
         [0069]    In the Macro-Cellular example provided by Table 1, the scenario uses the following weighting factors: 2/10 weighing to the Neighbor List  458 , 6/10 weighting to the User Radio Measurements  460 , 1/10 weighting to the Achievable Service Quality  455  and 1/10 weighting to the Loading Factor  456 . In this exemplary embodiment, the Target EBS with the lowest User Radio Measurements  460  (i.e. RF Strength) rank index is Target EBS 2  (the lowest score is the best potential handoff candidate). In other words, Target EBS 2  is ranked first out of the four possible EBSs for the User Radio Measurements  460  (i.e. RF Strength) rank index. This reflects the fact that, in this example, the Macro-Cellular network scenario emphasizes the User Radio Measurements  460  (i.e. RF Strength List) index by multiplying the index by a 6/10 weighting factor. Therefore, even though the Loading Factor  456  index of EBS 2  is ranked fourth out of the four possible EBSs, this particular index is de-emphasized in this Macro-Cellular network scenario by being multiplied by a 1/10 weighting factor. 
         [0070]    Table 3 illustrates an example of the Priority List  427  for the Macro-Cellular scenario. It is noted that Ranking Matrix  463  has been re-ranked according to the Macro-Cellular matrix entries (not shown). As illustrated in Table 3, Target EBS 2  has the lowest accumulated score in the Macro-Cellular field. Therefore, Mobile Device  102  would first attempt to handoff to Target EBS 2 . If for some reason Mobile Device  102  could not handoff to Target EBS 2 , then Mobile Device  102  would attempt the next entry in the Priority List  427 . In this example, Mobile Device  102  would attempt to handoff to Target EBS 1  since that is the next available Target EBS in the Macro-Cellular list. If Mobile Device  102  could not handoff to Target EBS 1 , then Mobile Device  102  would attempt to handoff to Target EBS 4  and Target EBS 3 , in order. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Priority List Ranked According to Macro-Cellular Scenario 
               
             
          
           
               
                   
                   
                   
                 Application - 
                   
                 Urban- 
                 
                   Macro- 
                 
               
               
                   
                 Geo- 
                 RF 
                 Service 
                   
                 Canyon 
                 
                   Cell 
                 
               
               
                 Target 
                 Neighbor 
                 Strength 
                 Quality 
                 Loading 
                 Ranking 
                 
                   Ranking 
                 
               
               
                   
               
               
                 EBS2 
                 2 
                 1 
                 1 
                 4 
                 1.9 
                 
                   1.5 
                 
               
               
                 EBS1 
                 1 
                 2 
                 4 
                 3 
                 
                   1.7 
                 
                 2.1 
               
               
                 EBS4 
                 4 
                 3 
                 3 
                 2 
                 3.5 
                 3.1 
               
               
                 EBS3 
                 3 
                 4 
                 2 
                 1 
                 2.9 
                 3.3 
               
               
                   
               
             
          
         
       
     
         [0071]    At  477 , the new Serving EBS will update the Intelligent Database  459  that a Successful Handoff  477  is completed. The new Serving EBS&#39; rank index will be increased in the Intelligent EBS Database  459 , regardless of whether the Urban-Canyon matrix of Table 2 or the Macro-Cellular matrix of Table 3 is utilized. 
         [0072]    Table 4 illustrates an example of a parsed down Priority List  427  for the Macro-Cellular scenario. It is noted that the Priority List  427  illustrated in Table 4 contains only “Target” and “Macro-Cell” entries from the Ranking Matrix  463 . This allows the amount of handoff traffic sent to the Mobile Device  102  to be reduced. As illustrated in Table 4, Target EBS 2  has the lowest accumulated score in the Macro-Cellular field. Therefore, Mobile Device  102  would first attempt to handoff to Target EBS 2 . If for some reason Mobile Device  102  could not handoff to Target EBS 2 , then Mobile Device  102  would attempt the next entry in the Priority List  427 . In this example, Mobile Device  102  would attempt to handoff to Target EBS 1  since that is the next available Target EBS in the Macro-Cellular list. If Mobile Device  102  could not handoff to Target EBS 1 , then Mobile Device  102  would attempt to handoff to Target EBS 4  and Target EBS 3 , in order. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Parsed Down Priority List Ranked According 
               
               
                 to Macro-Cellular Scenario 
               
             
          
           
               
                   
                   
                 Macro-Cell 
               
               
                   
                 Target 
                 Ranking 
               
               
                   
                   
               
               
                   
                 EBS2 
                 1.5 
               
               
                   
                 EBS1 
                 2.1 
               
               
                   
                 EBS4 
                 3.1 
               
               
                   
                 EBS3 
                 3.3 
               
               
                   
                   
               
             
          
         
       
     
         [0073]    Table 5 illustrates an example of a further parsed down Priority List  427  for the Macro-Cellular scenario. Table 5 illustrates an example of a further parsed down Priority List  427  for the Macro-Cellular scenario. It is noted that the Priority List  427  illustrated in Table 5 contains only two “Target” and “Macro-Cell” entries from the Ranking Matrix  463 . This allows the amount of handoff traffic sent to the Mobile Device  102  to be reduced. As illustrated in Table 5, Target EBS 2  has the lowest accumulated score in the Macro-Cellular field. Therefore, Mobile Device  102  would first attempt to handoff to Target EBS 2 . If for some reason Mobile Device  102  could not handoff to Target EBS 2 , then Mobile Device  102  would attempt the next entry in the Priority List  427 . In this example, Mobile Device  102  would attempt to handoff to Target EBS 1  since that is the next available Target EBS in the Macro-Cellular list. If Mobile Device  102  could not handoff to Target EBS 1 , then Mobile Device  102  would coordinate with the Serving EBS  104  in order to be handed off to a different EBS. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Parsed Down Priority List Ranked According 
               
               
                 to Macro-Cellular Scenario 
               
             
          
           
               
                   
                   
                 Macro-Cell 
               
               
                   
                 Target 
                 Ranking 
               
               
                   
                   
               
               
                   
                 EBS2 
                 1.5 
               
               
                   
                 EBS1 
                 2.1 
               
               
                   
                   
               
             
          
         
       
     
         [0074]      FIG. 5  illustrates another call flow example involving handoff preparation during a radio link failure (RLF), but prior to the Mobile Device  102  obtaining the Priority List  527 . Specifically,  FIG. 5  illustrates a call flow diagram, when a Mobile Device  102  is connected to a Serving EBS  104  and the Mobile Device  102  is to be handed off to a Target EBS. Prior to the handoff, Mobile Device  102  is connected to the Serving EBS  104  and is capable of transferring Packet Data  501   a  and  501   b  to the rest of the network (MME/SAE GW  120 ) via the Serving EBS  104 . 
         [0075]    The Serving EBS  104  configures the handset measurement control procedures at  505  in order to obtain a measurement report  509  from the Mobile Device  102 . Hence, in the example, the Mobile Device  102  receives the measurement control procedures and command at  505  from the Serving EBS  104  and subsequently sends a measurement report  509  of the surrounding EBS signal strengths, as measured by the Mobile Device  102 , to the Serving EBS  104 . The measurement report  509  can be sent either perodically or by a triggered event that is configured by the network  100 . In one embodiment, the measurement report  509  is a RF signal strength measurement as measured by Mobile Device  102 . 
         [0076]    Upon receiving the measurement report  509 , the Serving EBS  104  makes a handoff decision  513  to handoff the Mobile Device  102  to another EBS. However, in the procedure of  FIG. 5 , the Serving EBS  104  does not know at this instant in time, which EBS the Mobile Device  102  will be transferred to. The ultimate handoff destination will be determined from among Target EBS 1 , EBS 2 , . . . , or EBSn, based on a Ranking Matrix  463 . While this illustrated example shows two target EBSs, for simplicity, it is understood that there could possibly be N Target EBSs. 
         [0077]    Hence, in the example, the Serving EBS  104  sends a handoff request  517  to each potential Target EBS, that is to say to Target EBS 1   108  and Target EBS 2   110  in  FIG. 5 . The handoff request  517  contains context information of the Mobile Device  102 . 
         [0078]    Target EBS 1   108  and Target EBS 2   110  perform admission control  521  in order to gauge the available network resources. Furthermore, each Target EBS 1   108  and Target EBS 2   110  sends a handoff request acknowlegement  525  to the Serving EBS  104 . 
         [0079]    Additionally, both Target EBS 1   108  and Target EBS 2   110  store the Mobile Device  102  context information and reserve Layer 1/Layer 2 (L1/L2) resources in order to assist with the handoff. In one exemplary embodiment, the L1/L2 resources are CRNTI or access parameters. 
         [0080]    The Serving EBS  104  receives handoff request acknowlegements  525  from both Target EBS 1   108  and Target EBS 2   110 . Afterwards, the Serving EBS  104  generates a Priority List  527 . 
         [0081]    The Priority List  527  is a ranking of the available neighboring EBSs and is based on information such as cell size, carrier frequency, site location, capacity or loading, available services, signal strengths, etc. Furthermore, the Priority List  527  also contains stored information of neighboring EBSs&#39; loading condition, handset measurement report  509  and data application and service quality available at the neighboring EBSs. The Priority List  527  is generated based on the ranking matrix. Table 1 above shows an example of a ranking matrix, and examples of the Priority List  527  are illustrated in Tables 2 and 3 (discussed above). 
         [0082]    If the radio link fails resulting in a Radio Link Failure (RLF)  529 , then the Mobile Device  102  will not receive a Handoff Command Message, which typically instructs the Mobile Device  102  to connect to another Target EBS. However, the Mobile Device  102  will autonomously handoff to the best Target EBS based on current measurement control procedures  505  after the RLF  529 . If the best Target EBS has received context information from the Serving EBS  104 , then the Mobile Device  102  will not go through an idle-to-active transition. As a result, the Target EBS will be ready for the handoff of Mobile Device  102 . 
         [0083]    The Mobile Device  102  synchronizes with the Target EBS 1   108  via Sync+Timing Advance UL Allocation message  533 . Sync+Timing Advance UL Allocation message  533  also allows the Target EBS 1   108  to assign an uplink allocation and a timing advance to the Mobile Device  102 . 
         [0084]    Afterwards, the Mobile Device  102  sends an Access Message  537  to the Target EBS 1   108 . 
         [0085]    The Target EBS 1   108  performs a Path Update  541  to update the MME/SAE GW  120  of the handoff. After the Path Update  541  is completed, the Target EBS 1   108  sends a Resource Release Message  545  to the Serving EBS  104  to trigger the release of the system resources previously used by the Mobile Device  102  at the Serving EBS  104 . 
         [0086]    As a result of the handoff, Mobile Device  102  is connected to the Target EBS 1   108  and packet data is transferred with MME/SAE GW  120  via Packet Data messages  549  and  551 . 
         [0087]      FIG. 6  illustrates another call flow example involving handoff preparation during a RLF, after the Mobile Device  102  receives the Priority List  627 . Specifically,  FIG. 6  illustrates a call flow diagram, when a Mobile Device  102  is connected to a Serving EBS  104  and the Mobile Device  102  is to be handed off to a Target EBS. Prior to the handoff, Mobile Device  102  is connected to the Serving EBS  104  and is capable of transferring Packet Data  601   a  and  601   b  to the rest of the network (MME/SAE GW  120 ) via the Serving EBS  104 . 
         [0088]    The Serving EBS  104  configures the handset measurement control procedures at  605  in order to obtain a measurement report  609  from the Mobile Device  102 . Hence, in the example, the Mobile Device  102  receives the measurement control procedures and command at  605  from the Serving EBS  104  and subsequently sends a measurement report  609  of the surrounding EBS signal strengths, as measured by the Mobile Device  102 , to the Serving EBS  104 . The measurement report  609  can be sent either perodically or by a triggered event that is configured by the network  100 . In one embodiment, the measurement report  609  is a RF signal strength measurement as measured by Mobile Device  102 . 
         [0089]    Upon receiving the measurement report  609 , the Serving EBS  104  makes a handoff decision  613  to handoff the Mobile Device  102  to another EBS. However, in the procedure of  FIG. 6 , the Serving EBS  104  does not know at this instant in time, which EBS the Mobile Device  102  will be transferred to. The ultimate handoff destination will be determined from among Target EBS 1 , EBS 2 , . . . , or EBSn, based on a Ranking Matrix  463 . While this illustrated example shows two target EBSs, for simplicity, it is understood that there could possibly be N Target EBSs. 
         [0090]    Hence, in the example, the Serving EBS  104  sends a handoff request  617  to each potential Target EBS, that is to say Target EBS 1   108  and Target EBS 2   110  in  FIG. 6 . The handoff request  617  contains context information of the Mobile Device  102 . 
         [0091]    Target EBS 1   108  and Target EBS 2   110  perform admission control  621  in order to gauge the available network resources. Furthermore, each Target EBS 1   108  and Target EBS 2   110  sends a handoff request acknowlegement  625  to the Serving EBS  104 . 
         [0092]    Additionally, both Target EBS 1   108  and Target EBS 2   110  store the Mobile Device  102  context information and reserve Layer 1/Layer 2 (L1/L2) resources in order to assist with the handoff. In one exemplary embodiment, the L1/L2 resources are CRNTI or access parameters. 
         [0093]    The Serving EBS  104  receives handoff request acknowlegements  625  from both Target EBS 1   108  and Target EBS 2   110 . Afterwards, the Serving EBS  104  generates a Priority List  627 . 
         [0094]    The Priority List  627  is a ranking of the available neighboring EBSs and is based on information such as cell size, carrier frequency, site location, capacity or loading, available services, signal strengths, etc. Furthermore, the Priority List  627  also contains stored information of neighboring EBSs&#39; loading condition, handset measurement report  609  and data application and service quality available at the neighboring EBSs. The Priority List  627  is generated based on the ranking matrix. Table 1 above shows an example of a ranking matrix, and examples of the Priority List  627  are illustrated in Tables 2 and 3 (discussed above). 
         [0095]    The Serving EBS  104  attempts to direct the Mobile Device  102 , via a Handoff Command Message  629 , to handoff to a Target EBS (in this example EBS  108 ). The Handoff Command Message  629  will contain either the whole Priority List  627  or the top-ranked Target EBS from the Priority List  627 . 
         [0096]    The Mobile Device  102  receives the Handoff Command message  629  from the Serving EBS  104  with the Priority List  627  and begins contacting potential target EBSs based on the Priority list  627 . In the example of  FIG. 6 , we will assume that the EBS 1   108  ranks highest on the Priority List. 
         [0097]    However, in this example RLF  630  occurs resulting in a radio link failure between the Mobile Device  102  and Target EBS 1   108 . The Mobile Device  102  will attempt to connect to the Target EBS 1   108 , but will Fail to Attach  631 . Therefore, the Mobile Device  102  cannot be synchronized with EBS 1   108  and cannot attach to the Target EBS 1   108 . However, the Mobile Device  102  will autonomously attempt to attach to the next available Target EBS in the Priority List  627 . If another radio link failure occurs, then the Mobile Device  102  will attempt to connect to the subsequent EBS contained in the Priority List  627 , according to the priority list ranking. 
         [0098]    The Mobile Device  102  synchronizes with the Target EBS 2   110  via Sync+Timing Advance UL Allocation message  633 . Sync+Timing Advance UL Allocation message  633  also allows the Target EBS 2   110  to assign an uplink allocation and a timing advance to the Mobile Device  102 . 
         [0099]    Afterwards, the Mobile Device  102  sends an Access Message  637  to the Target EBS 2   110 . 
         [0100]    The Target EBS 2   110  performs a Path Update  641  to update the MME/SAE GW  120  of the handoff. After the Path Update  641  is completed, the Target EBS 2   110  sends a Resource Release Message  645  to the Serving EBS  104  to trigger the release of the system resources previously used by the Mobile Device  102  at the Serving EBS  104 . 
         [0101]    As a result of the handoff, Mobile Device  102  is connected to the Target EBS 2   110  and packet data is transferred with MME/SAE GW  120  via Packet Data messages  649  and  651 . 
         [0102]      FIG. 7  illustrates another call flow example involving handoff preparation during a RLF, but prior to preparation of the Priority List  727 . Specifically,  FIG. 7  illustrates a call flow diagram, when a Mobile Device  102  is connected to a Serving EBS  104  and the Mobile Device  102  is to be handed off to a Target EBS. Prior to the handoff, Mobile Device  102  is connected to the Serving EBS  104  and is capable of transferring Packet Data  701   a  and  701   b  to the rest of the network (MME/SAE GW  120 ) via the Serving EBS  104 . 
         [0103]    The Serving EBS  104  configures the handset measurement control procedures at  705  in order to obtain a measurement report  709  from the Mobile Device  102 . Hence, in the example, the Mobile Device  102  receives the measurement control procedures and command at  705  from the Serving EBS  104  and subsequently sends a measurement report  709  of the surrounding EBS signal strengths, as measured by the Mobile Device  102 , to the Serving EBS  104 . The measurement report  709  can be sent either perodically or by a triggered event that is configured by the network  100 . In one embodiment, the measurement report  709  is a RF signal strength measurement as measured by Mobile Device  102 . 
         [0104]    Upon receiving the measurement report  709 , the Serving EBS  104  typically makes a handoff decision (not shown) to handoff the Mobile Device  102  to another EBS. However, in this exemplary embodiment a RLF (not shown) occurs, resulting in a radio link failure between the Mobile Device  102  and the Serving EBS  104 . 
         [0105]    The Serving EBS  104  automatically detects the RLF. 
         [0106]    The Serving EBS  104  determines potential Target EBSs based on a ranking matrix generated from previous measurement reports and intelligent database  459 , similar to Handoff Decision  413  in  FIG. 4   a.    
         [0107]    Hence, in the example, the ultimate handoff destination, Target EBS  727 , will be determined from among Target EBS 1 , EBS 2 , . . . , or EBSn, based on the Ranking Matrix  463 , generated from the previous measurement reports and Intelligent Database  459 . The Ranking Matrix  463  is similar to that utilized in  FIG. 4   a - b . While this example shows two target EBSs, for simplicity, it is understood that there could possibly be N Target EBSs. Although the Serving EBS  104  has already determined Target EBS  727 , the possibility exists for another RLF. Therefore, the Serving EBS  104  transfers Context Information  731  to multiple Target EBSs; specifically Target EBS 1 , EBS 2 , . . . , or EBSn. This ensures that the various Target EBSs have the capacity to support communication with Mobile Device  102  in the case of another RLF. 
         [0108]    The Mobile Device  102  synchronizes with the Target EBS 2   110  via Sync+Timing Advance UL Allocation message  733 . Sync+Timing Advance UL Allocation message  733  also allows the Target EBS 2   110  to assign an uplink allocation and a timing advance to the Mobile Device  102 . 
         [0109]    Afterwards, the Mobile Device  102  sends an Access Message  737  to the Target EBS 2   110 . 
         [0110]    The Target EBS 2   110  performs a Path Update  741  to update the MME/SAE GW  120  of the handoff. After the Path Update  741  is completed, the Target EBS 2   110  sends a Resource Release Message  745  to the Serving EBS  104  to trigger the release of the system resources previously used and the Mobile Device  102  at the Serving EBS  104 . 
         [0111]    As a result of the handoff, Mobile Device  102  is connected to the Target EBS 2   110  and packet data is transferred with MME/SAE GW  120  via Packet Data messages  749  and  751 . Furthermore, if Target EBS 2   110  received context information from the Serving EBS  104  (as described above), then the Mobile Device  102  will avoid going through idle-to-active transitioning resulting in a reduction in handoff preparation latency. Therefore, the handoff robustness of the system will be improved. 
         [0112]    As shown by the above discussion, many of the functions relating to the distinguishing the human user from an automation handoff processing in the EBS, such as developing the ranking matrix and the priority list, are implemented on processors in the EBS. 
         [0113]    As known in the data processing and communications arts, such a processor typically comprises a central processing unit (CPU) or similar device, an internal communications bus, various types of memory or storage media (RAM, ROM, EEPROM, cache memory, disk drives, etc.) for code and data storage, and one or more network or other interface cards or ports for inter-device communication purposes. The software functionalities involve programming, including executable code as well as associated stored data, e.g. objects for the data processing and related signaling performed by the EBS. The software code is executable by the CPU. In operation, the code is stored within the storage media in or associated with the CPU. At other times, however, the software may be stored at other locations and/or transported for loading into the appropriate EBS. Execution of such code by a processor of the EBS enables the EBS platform to implement the methodology for handoff in essentially the manner performed in the embodiments discussed and illustrated herein. As used herein, terms such as computer or machine “readable medium” therefore refer to any storage medium capable of participating in providing instructions to a processor for execution. 
         [0114]    The concepts discussed above are amenable to a variety of changes and/or adaptations. For example, in the specific examples above, the ranking matrix and the priority list were generated in the Serving EBS. Those skilled in the art will recognize, however, that such processing may be implemented in other network nodes such as a base station controller (if provided separately), the gateway, etc. 
         [0115]    While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings. 
       Appendix: Acronym List 
       [0116]    The description above has used a large number of acronyms to refer to various services, messages and system components. Although generally known, use of several of these acronyms is not strictly standardized in the art. For the convenience of the reader, the following list correlates terms to acronyms, as used in the detailed description above. 
         [0117]    CDMA—Code Division Multiple Access 
         [0118]    EBS—Enhanced Base Station 
         [0119]    LTE—Long Term Evolution 
         [0120]    AP—Access Point 
         [0121]    WiMAX—Worldwide Interoperability for Microwave Access 
         [0122]    UMB—Ultra Mobile Broadband 
         [0123]    EVDO—Evolution Data Only 
         [0124]    GW—Gateway 
         [0125]    Tx—Transmitter 
         [0126]    Rx—Receiver 
         [0127]    MAC—Media Access Control 
         [0128]    RLC—Radio Link Control 
         [0129]    ROHC—Robust Header Compression 
         [0130]    IP—Internet Protocol 
         [0131]    UDP—User Datagram Protocol 
         [0132]    RTP—Real-time Transport Protocol 
         [0133]    TCP—Transmission Control Protocol 
         [0134]    R—Radio Frequency 
         [0135]    CRNTI—Cell Radio Network Temporary Identifier 
         [0136]    NGN—Next Generation Network 
         [0137]    AMPS—Advanced Mobile Phone System 
         [0138]    TDMA—Time Division Multiple Access 
         [0139]    GSM—Global System for Mobile communications 
         [0140]    UE—User Equipment 
         [0141]    UL—UpLink 
         [0142]    L1/L2—Layer 1/Layer 2 
         [0143]    EBS—Evolved Base Station 
         [0144]    aGW—access GateWay 
         [0145]    eRNC—evolved Radio Network Controller 
         [0146]    MME—Mobility Management Entity 
         [0147]    SAE—System Architecture Evolution 
         [0148]    CRNTI—Cellular Radio Network Temporary Identifier