PATENT DOCUMENT

Publication Number: US-10225777-B2
Application Number: US-201615166708-A
Country: US
Kind Code: B2

Title: Apparatus, systems and methods for an enhanced handover mechanism and cell re-selection

Abstract:
A user equipment (UE), base station and a corresponding method for receiving historical data from a diagnostic server, receiving location data of the UE, determining a probability of a failed handover during a call based on the historical data and the location data, comparing the probability of the failed handover to a threshold value and initiating a call handover to a wireless local area network when the probability of the failed handover exceeds the threshold value. Also, a UE, base station and corresponding method for determining if one or more UEs have an active voice over WiFi call or if the UEs are registered with a Internet protocol (“IP”) multimedia subsystem (“IMS”) over WiFi and biasing a cell reselection procedure of the UE to select a cell of a packet switched network such as LTE.

Claims:
The invention claimed is: 
     
       1. A method, comprising:
 at a user equipment (“UE”) connected to a packet switched cellular network:
 receiving historical data from a diagnostic server, the historical data including handover data for call handovers occurring on the packet switched cellular network; 
 receiving location data of the UE; 
 determining a probability of a failed handover from a first base station of the packet switched cellular network to a second base station of the packet switched cellular network during a call on the packet switched cellular network based on the historical data and the location data; 
 comparing the probability of the failed handover to a threshold value; 
 determining whether a wireless local area network is available to the UE at a location corresponding to the location data; and 
 initiating a call handover from the packet switched cellular network to the wireless local area network when the probability of the failed handover exceeds the threshold value and the wireless local area network is available. 
 
 
     
     
       2. The method of  claim 1 , further comprising:
 reporting, by the UE, further historical data to the diagnostic server. 
 
     
     
       3. The method of  claim 1 , further comprising:
 determining, by the UE, that the wireless local area network is not available; and 
 initiating a second call handover to a further network, wherein the further network is a circuit switched network. 
 
     
     
       4. The method of  claim 3 , further comprising:
 when the circuit switched network is not available, re-initiating the call handover to the wireless local area network. 
 
     
     
       5. The method of  claim 1 , wherein the historical data includes one of prior failed handover data or measurement thresholds. 
     
     
       6. The method of  claim 1 , wherein the comparing is performed when the UE is connected to an LTE network and the call is a Voice over LTE (VOLTS) call, the method further comprising:
 receiving the threshold value from an evolved Node B (eNB) of the LTE network. 
 
     
     
       7. The method of  claim 1 , wherein the probability of the failed handover includes a first probability at a serving cell and a second probability at a neighboring cell. 
     
     
       8. The method of  claim 1 , wherein the failed handover is a Single Radio Voice Call Continuity (“SRVCC”) call failure. 
     
     
       9. A user equipment (“UE”) device comprising:
 a non-transitory memory having a program stored thereon; and 
 a processor, wherein execution of the program causes the processor to perform operations comprising:
 receiving historical data from a diagnostic server, the historical data including handover data for call handovers occurring on a packet switched cellular network, 
 receiving location data of the UE, 
 determining a probability of a failed handover from a first base station of the packet switched cellular network to a second base station of the packet switched cellular network during a call on the packet switched cellular network based on the historical data and the location data, 
 comparing the probability of the failed handover to a threshold value, 
 determining whether a wireless local area network is available to the UE at a location corresponding to the location data, and 
 initiating a call handover from the packet switched cellular network to the wireless local area network when the probability of the failed handover exceeds the threshold value and the wireless local area network is available. 
 
 
     
     
       10. The UE device of  claim 9 , wherein the processor includes a baseband processor and an application processor. 
     
     
       11. A method, comprising:
 at a base station:
 receiving historical data from a diagnostic server, the historical data including handover data for call handovers occurring on a packet switched cellular network; 
 receiving location data from a user equipment (“UE”); 
 receiving, by the base station, an inter-radio access technology (“IRAT”) evaluation request from the UE; 
 evaluating a wireless local area network based on the location data; and 
 recommending a WiFi link preference to the UE for a call handover from the packet switched cellular network. 
 
 
     
     
       12. The method of  claim 11 , further comprising:
 calculating a pre-threshold value based on the historical data and location data; and 
 transmitting the pre-threshold value to the UE. 
 
     
     
       13. A method, comprising:
 at user equipment (“UE”):
 determining if the UE has an active voice over WiFi call or if the UE is registered with an internet protocol (“IP”) multimedia subsystem (“IMS”) over WiFi; and 
 when the UE has an active voice over WiFi call or is registered with the IMS over WiFi, biasing a cell reselection procedure of the UE to select a cell of a packet switched cellular network. 
 
 
     
     
       14. The method of  claim 13 , wherein the packet switched cellular network is one a Long Term Evolution (LTE) network or an LTE-Advanced network. 
     
     
       15. The method of  claim 13 , further comprising:
 initiating the cell reselection procedure to select the cell of the packet switched cellular network. 
 
     
     
       16. The method of  claim 15 , further comprising:
 when the cell selection procedure successfully selects the cell of the packet switched cellular network, initiating a handover of the voice over WiFi call to the packet switched cellular network. 
 
     
     
       17. The method of  claim 15 , further comprising:
 when the cell selection procedure does not successfully select the cell of the packet switched cellular network, initiating the cell reselection procedure to select a cell of a circuit switched network.

Description:
PRIORITY CLAIM/INCORPORATION BY REFERENCE 
     This application claims priority to U.S. Provisional Application 62/235,217 entitled “Apparatus, Systems and Methods for an Enhanced Handover Mechanism and Cell Re-Selection,” filed on Sep. 30, 2015, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Wireless communication systems are rapidly growing in usage. Further, wireless communication technology has evolved from voice-only communications to also include the transmission of data, such as Internet and multimedia content. A user equipment (“UE”) may be configured to establish a connection with different types of networks through the use of wireless communications protocols. Accordingly, based upon the capabilities of the hardware and software of the UE, the connection may be made with these different types of networks. For instance, the network may be a Universal Mobile Telecommunication System (“UMTS”) or Long Term Evolution (“LTE”) network for data connectivity, or the network may be a Global System for Mobile Communications (“GSM”) or Code Division Multiple Access (“CDMA”) network for voice connectivity. 
     LTE, commonly referred to a “4G LTE,” is a standard for wireless communication of high-speed data for mobile phones and data terminals. The LTE standard has been developed by the 3rd Generation Partnership Project (“3GPP”) and is described as a natural upgrade path for carriers using prior generation networks or “legacy” protocols or 2G/3G networks, such as GSM/UMTS protocols and CDMA 2000 1× (e.g., 1×RTT or simply “1×”) wireless communication protocols. Each of these different types of networks and protocols may be termed radio access technologies (“RATs”). 
     Through the usage of an all-Internet Protocol (“IP”) network, the LTE standard supports only packet switching (“PS”) data transmissions. Similar to many other protocols, an IP network breaks data into blocks and wraps the blocks into structures called packets. Each packet contains, along with the data load, information about the IP address of the source and the destination nodes, sequence numbers, control information, etc. In a circuit switched (“CS”) network, the communication channel remains open and in use throughout the duration of the call and the call data is transmitted all at once without being broken into blocks. 
     Since voice calls in GSM, UMTS and CDMA2000 utilize circuit switched data transmissions, carriers adopting the LTE standard need to re-engineer their voice call network. For instance, Voice over LTE (“VoLTE”) uses an IP multimedia subsystem (“IMS”) network having specific profiles for control and media planes of voice service on LTE. Accordingly, VoLTE communications result in the voice service being delivered as data flows within the LTE data bearer. Thus, there is no requirement for the legacy circuit-switched voice network to be maintained. Furthermore, VoLTE communications has up to three times more voice and data capacity than UMTS networks and up to six times more than GSM networks. 
     Furthermore, the 3GPP has standardized Single Radio Voice Call Continuity (“SRVCC”) to provide easy handovers from an LTE network to a GSM/UMTS network. Accordingly, SRVCC functionality is needed within VoLTE systems to enable a VoLTE call to be seamlessly handed over to legacy circuit switched voice systems, such as 2G/3G networks. However, SRVCC handover failures continue to be significant, especially in cell edge cases, where the coverage for LTE and legacy RATs is typically insufficient. Thus, the SRVCC handover failures not only result in call failures, but also decreased audio quality resulting in unsatisfactory user experience. 
     SUMMARY 
     Described herein are apparatus, systems and methods for an enhanced handover mechanism. For instance, the exemplary embodiments may pertain to enhanced SRVCC call reliability through the use of Interworking Wireless Local Area Network (“iWLAN”) handover mechanisms. Furthermore, described herein are apparatus, systems and methods for enhanced cell re-selection and traffic steering. For instance, further exemplary embodiments may pertain to caller-aware cell re-selection for wireless network voice calls. 
     A method may comprise receiving, by a user equipment (“UE”), historical data from a diagnostic server, receiving location data of the UE, determining a probability of a failed handover (e.g., an SRVCC handover) during a call based on the historical data and the location data, comparing the probability of the failed handover to a threshold value, and initiating a call handover to a wireless local area network when the probability of the failed handover exceeds the threshold value. 
     Also described herein is a device comprising a non-transitory memory having a program stored thereon, an application processor and a baseband processor. The execution of the program causes the processor to perform operations comprising receiving historical data from a diagnostic server, receiving location data of the UE, determining probability of a failed handover during a call based on the historical data and the location data, comparing the probability of the failed handover to a threshold value, initiating a call handover to a wireless local area network when the probability of the failed handover exceeds the threshold value. 
     Further described herein is a method comprising receiving, by a base station or a UE, historical data from a diagnostic server, receiving, by the base station or the UE, location data from a UE, calculating a pre-threshold value based on the historical data and location data, transmitting the pre-threshold value to the UE, receiving an IRAT evaluation request from the UE, evaluating a wireless local area network based on the location data, and recommending a WiFi link preference to the UE for a call handover. It may be noted that the above-described method may be performed at either the base station (e.g., eNodeB) or, alternatively, at the device (e.g., the UE) without requiring any change in the base station. 
     Further described herein is a method comprising establishing, by a UE, a voice over WiFi call within a network, the network including a wireless local area network and an LTE network, determining a state of the voice over WiFi call, determining that the UE is registered with an IMS, selecting an LTE network cell over a legacy network cell for the UE to camp on, and initiating a call handover from a wireless local area network to the LTE network based on the state of the voice over WiFi call. 
     Further described herein is a system comprising determining, by a base station, a state of the voice over WiFi calling by a plurality of UEs within a network, the network including a wireless local area network and an LTE network, determining an IMS registration of each of the plurality of the UEs, setting a priority for network traffic steering based on the IMS registrations and/or a number of active WiFi calls on the network, adjusting the priority based on a change in one of the IMS registrations and the number of active WiFi calls on the network, and broadcasting a system information block (“SIB”) message to the plurality of UEs based on the priority. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exemplary network arrangement for an enhanced handover mechanism, according to various embodiments described herein. 
         FIG. 2  shows an exemplary method for an enhanced handover mechanism a mobile device, such as the UE, in a communication with a plurality of wireless networks, such as LTE-RAN and iWLAN, according to various embodiments described herein. 
         FIG. 3  shows an exemplary method for an enhanced handover mechanism a mobile device, such as the UE, in a communication with a plurality of wireless networks, such as LTE-RAN and iWLAN, according to various embodiments described herein. 
         FIG. 4  shows an exemplary method for an enhanced handover mechanism by a base station, such as the eNB, in a communication with the UE and a plurality of wireless networks, such as LTE-RAN and the iWLAN, according to various embodiments described herein. 
         FIG. 5  shows an exemplary method for enhanced cell re-selection according to various embodiments described herein. 
         FIG. 6  shows an exemplary method for enhanced network traffic steering according to various embodiments described herein. 
         FIG. 7  shows an exemplary UE according to various embodiments described herein. 
     
    
    
     DETAILED DESCRIPTION 
     The exemplary embodiments may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiments describe an apparatus, system and method for an enhanced handover mechanism from an LTE network to a wireless local network. For instance, the exemplary embodiments may pertain to enhanced SRVCC call reliability through the use of exemplary WLAN handover mechanisms. Furthermore, described herein are apparatus, systems and methods for enhanced cell re-selection and traffic steering. For instance, further exemplary embodiments may pertain to caller-aware cell re-selection for wireless network voice calls. 
     In the exemplary embodiments, the mobile device will be described as a UE associated with LTE networks. However, it will be understood by those skilled in the art that UEs operating in accordance with other network standards may also implement the exemplary embodiments in accordance with the functionalities and principles described herein. These network standards may also include further evolutions of the current network standards, e.g., 5G standards. 
     The LTE-RAN may be a portion of the cellular networks deployed by cellular providers or operators (e.g., Verizon, AT&amp;T, Sprint, T-Mobile, etc.). These networks may include, for example, base client stations (Node Bs, eNodeBs, HeNBs, etc.) that are configured to send and receive traffic from UEs that are equipped with an appropriate cellular chip set. In addition to the LTE-RAN, the operators may also include legacy RANs that are generally labeled as 2G and/or 3G networks and may utilize circuit switched voice calls and packet switched data operations. Those skilled in the art will understand that the cellular providers may also deploy other types of networks, including further evolutions of the cellular standards, within their cellular networks. 
     As will be described in greater detail below, operators may deploy an IP Multimedia Subsystem (“IMS”). The IMS may be generally described as an architecture for delivering multimedia services to the UE using the IP protocol. In the context of the LTE-RAN, the IMS may provide an exemplary UE with voice capabilities (e.g., VoLTE) as well as Short Messaging Services (“SMS”) capabilities. In the context of legacy RANs, the IMS may also provide the UE with SMS services. 
     In addition to the LTE-RAN and 2G/3G networks, the exemplary UE may also be capable of integrating WiFi communications into its operation, wherein the UE may seamlessly handover between Wi-Fi and mobile networks. For instance, 3GPP has worked out specifications for the integration of WiFi and 3GPP networks using the “iWLAN” standard. This is also known as S2b based WLAN interworking. An IWLAN-capable device may use GSM signaling for voice services over circuit-switched UMTS Terrestrial Radio Access Network (“UTRAN”) access but Session Initiation Protocol (“SIP”) signaling for voice services over WiFi access or Voice over LTE. 
     According to the exemplary embodiments, the systems and methods described herein provide for an enhanced solution to use alternative iWLAN technology. For instance, the systems and methods may allow for a call to reliably continue on iWLAN (e.g., WiFi) with a similar audio experience whenever a handover from a VoLTE call is necessary. Accordingly, the UE is able to utilize WiFi coverage to continue the call over WiFi-based IMS infrastructure as an alternative to choosing the less reliable 3G radio coverage and infrastructure. 
     As will be described in greater detail below, the exemplary embodiments may utilize historical data that is periodically reported by the UE to a diagnostic server or other network component. This historical data may include previously reported SRVCC call failures occurring on the current serving cell, as well as measurement threshold information, handover threshold information, prior triggering events, etc. 
     Within the field of LTE measurement and reporting, events (e.g., A 1 -A 5 , B 1 -B 2 , etc.) may be triggered as the radio conditions of a network changes. For instance, A 1 -A 5  events are based on Reference Signal Received Power (“RSRP”) and Reference Signal Received Quality (“RSRQ”) information. For example, an A 1  event may trigger when the serving cell conditions become better than a threshold value, an A 2  event may trigger when the serving cell conditions become worse than the threshold value, etc. B 1 -B 2  events are inter-system LTE events that are triggered based on the various conditions specific to a different RAT (e.g., UMTS, GSM, CDMA2000, etc.). A B 1  event may trigger when the conditions at an inter-RAT neighbor become better than a threshold value. A B 2  event may trigger when the serving cell conditions become worse than a first threshold value and the conditions at an inter-RAT neighbor become better than a second threshold value. Thus, each occurrence of any of these events may be reported to the diagnostic server and stored as historical data. 
     Accordingly, the UE may use both its current location and this historical data received from the diagnostic server to evaluate whether the SRVCC call failures are a significant issue with its current serving cell and its configured neighboring cell(s). The UE may determine that the SRVCC call failures are significant based on a comparison to a predetermined threshold for a failure rate percentage (e.g., greater than 5% failure rate by the operator). Thus, once the SRVCC call failures are deemed to be a significant problem, the UE may then handover the call to iWLAN instead of attempting the SRVCC to one of the legacy RATs. 
       FIG. 1  shows an exemplary network arrangement  100  according to various embodiments described herein. The exemplary network arrangement  100  includes the UE  110 . Those skilled in the art will understand that the UE  110  may be any type of electronic component that is configured to communicate via a network, e.g., mobile phones, tablet computers, desktop computers, smartphones, phablets, embedded devices, wearables, etc. The UE  110  may be configured to perform cellular and/or WiFi functionalities and may include processors (e.g., application processors, baseband processors, etc.), memory arrangements, displays, transceivers, etc. It should also be understood that an actual network arrangement may include any number of UEs being used by any number of users and being associated with any number of these users where the user may be associated with one or more UEs. That is, the example of one UE  110  is only provided for illustrative purposes. 
     The UE  110  may be configured to communicate directly with one or more networks. In this example, the networks with which the UE  110  may communicate are a legacy radio access network (“RAN”)  120 , a LTE RAN (LTE-RAN)  122 , and a iWLAN  124 . More specifically, the legacy RAN  120  may be a circuit switched network, e.g., GSM, UMTS, CDMA, 1×RTT, 1×, etc. In this example, each of the networks  120 - 124  is a wireless network with which the UE  110  may communicate wirelessly. However, it should be understood that the UE  110  may also communicate with other types of networks and may also communicate using a wired connection. 
     With regards to the exemplary embodiments, the UE  110  may establish a connection with the LTE-RAN  122  to, among other functionalities, perform data transfers, voice calls and exchange SMS messages with the LTE network. In another example, the UE  110  may communicate with the legacy RAN  120  to perform some or all of the same functionalities, depending, for example, on the availability of a connection between the UE  110  and the LTE-RAN  122 . 
     The network arrangement  100  also includes a cellular core network  130  and the Internet  140 . The cellular core network  130 , the legacy RAN  120 , and the LTE-RAN  122  may be considered a cellular network that is associated with a particular cellular provider (e.g., Verizon, AT&amp;T, Sprint, T-Mobile, etc.). The cellular core network  130  may be considered to be the interconnected set of components that manages the operation and traffic of the cellular network. The interconnected components of the cellular core network  130  may include any number of components such as servers, switches, routers, etc. The cellular core network  130  also manages the traffic that flows between the cellular network and the Internet  140 . 
     As described above, the network arrangement  100  also includes an IMS  150  to provide the UE  110  with voice capabilities (e.g., VoLTE) and messaging capabilities (e.g., SMS). The UE  110 , in order to use the services provided by the IMS  150 , needs to register with the IMS  150 . The IMS  150  may include a variety of components to accomplish these tasks. For example, a typical IMS  150  includes a Home Subscriber Server (“HSS”) that stores subscription information for a user of the UE  110 . This subscription information is used to provide the correct multimedia services to the user. The IMS  150  may communicate with the cellular core network  130  and the Internet  140  to provide the multimedia services to the UE  110 . The IMS  150  is shown in close proximity to the cellular core network  130  because the cellular provider typically implements the functionality of the IMS  150 . However, it is not necessary for this to be the case such as when the IMS  150  is provided by another party. Thus, the network arrangement  100  allows the UE  110  to perform functionalities generally associated with computers and cellular networks. 
     The network arrangement  100  may also include a network services backbone  160  that is in communication either directly or indirectly with the Internet  140  and the cellular core network  130 . The network services backbone  160  may be generally described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a suite of services that may be used to extend the functionalities of the UE  110  in communication with the various networks. The network services backbone  160  may interact with the UE  110  and/or the networks  120 ,  122 ,  124 ,  130 , and  140  to provide these extended functionalities. 
     The network services backbone  160  may be provided by any entity or a set of entities. In one example, the network services backbone  160  is provided by the supplier of the UE  110 . In another example, the network services backbone  160  is provided by the cellular network provider. In still a further example, the network services backbone  160  is provided by a third party unrelated to the cellular network provider or the supplier of the UE  110 . 
     The exemplary embodiments relate to the UE  110  connecting to LTE-RAN  122  via an eNB  122 A. Initially, the UE  110  may establish a connection to the LTE-RAN  122 . Those skilled in the art will understand that any association procedure may be performed for the UE  110  to connect to the LTE-RAN  122 . For example, as discussed above, the LTE-RAN  122  may be associated with a particular cellular provider where the UE  110  and/or the user thereof has a contract and credential information (e.g., stored on a SIM card). Upon detecting the presence of the LTE-RAN  122 , the UE  110  may transmit the corresponding credential information to associate with the LTE-RAN  122 . More specifically, the UE  110  may associate with a specific access point (e.g., the eNB  122 A of the LTE-RAN  122 ). 
     As described above, when the UE  110  is associated with the LTE-RAN  122 , the UE  110  may register with the IMS  150  to receive certain services such as VoLTE and SMS services. As part of registering with the IMS  150 , the UE  110  will configure its internal stack to an LTE protocol stack. In addition, since the services will be provided using the IP based network, the UE  110  may also receive an IP address. 
     The network arrangement  100  may also include a diagnostic server  170  that is in communication either directly or indirectly with the eNB  122 A and the UE  110 . The diagnostic server  170  may receive and store historical data and statistics related to the network  100 . For instance, the diagnostic server  170  may store information such as measurement statistics, handover threshold data, and the failure percentages of SRVCC call handovers. The failures may be categorized in any number of manners, such as, in general, specific to the UE  110 , specific to the eNB  122 A, specific to neighboring eNBs, etc. Accordingly, the information stored in the diagnostic server  170  may be retrieved by the eNB  122 A and used in the calculation of further threshold information. One exemplary threshold may be termed a pre-B 2  event threshold. As noted above, the B 2  event may be triggered when the serving cell conditions become worse than a first threshold value and the conditions at an inter-RAT (“IRAT”) neighbor become better than a second threshold value. Accordingly, the pre-B 2  threshold may be used in order to take action before the B 2  threshold is reached. As will be described in greater detail below, the exemplary eNB  122 A may include an IRAT module  125  to evaluate the WiFi conditions of the iWLAN  124 . It should be noted that the network arrangement  100  shows the diagnostic server  170  being directly connected to the IRAT module  125  of the eNB  122 A. This is only exemplary and the diagnostic server  170  may be located anywhere within the network arrangement  100 , including, but not limited to, within the cellular core network  130 , as a separate component connected to the cellular core network  130  and/or the Internet  140  (e.g., in the same manner as the IMS  150  and the network services backbone  160 ), as a component of the network services backbone  160 , etc. 
       FIG. 2  shows an exemplary method  200  for an enhanced handover mechanism a mobile device, such as the UE  110 , in a communication with the eNB  122 A and a plurality of wireless networks, such as LTE-RAN  122  and the iWLAN  124 , according to various embodiments described herein. Thus, the method  200  will be described with reference to the components of the network arrangement  100  of  FIG. 1 . 
     According to one exemplary embodiment of the method  200 , in  205  the UE  110  may have a VoLTE call in progress. During the VoLTE call, the UE  110  may monitor the current radio conditions and report the information to the eNB  122 A. In the exemplary embodiments, some example radio condition parameters will be used to describe the exemplary operation. However, it should be understood that these parameters are only exemplary and other parameters that provide information about the radio conditions may also be used. 
     In  210 , the UE  110  may encounter poor LTE coverage and trigger an A 2  event. As noted above, an A 2  event may be triggered when the conditions associated with the current serving cell (e.g., eNB  122 A) become worse than a threshold value, for example, based on RSRP or RSRQ information. As result of the A 2  event, the UE  110  may be instructed by the eNB  122 A to perform measurements for neighboring cells. For instance, the neighboring cells may be signaled via one or more system information blocks (“SIBs”). The UE  110  may periodically report the results of the measurements to the diagnostic server  170  and the cellular core network  130 . 
     In  215 , the UE  110  may retrieve location data of the UE  110  as well as previously recorded historical data from the diagnostic server  170 . As discussed above, this historical data may include previously reported SRVCC call failures occurring on the current serving cell, as well as measurement threshold information, handover threshold information, prior triggering events (e.g., B 2  events), etc. 
     In  220 , the UE  110  or the eNB  122 A may calculate a pre-B 2  threshold based on the location data and the historical data. The pre-B 2  threshold may be defined as having a threshold value less than the threshold required by the UE  110  to trigger and report a B 2  event to the eNB  122 A. Once, the UE  110  calculates the pre-B 2  threshold, this value may then be reported to the baseband processor of the UE  110 . As described above, when the B 2  threshold is reached, this may trigger the UE  110  to perform an SRVCC handover to the legacy RAN  120  to maintain the current call. However, the pre-B 2  threshold is calculated and used to potentially have the UE  110  attempt to avoid the SRVCC handover and rather, perform a handover to the IWLAN  224  to maintain the call. As described above, the pre-B 2  threshold may be calculated based on current measurements made by the UE  110  and the historical data maintained by the diagnostic server  170 . For example, if the historical data maintained by the diagnostic server  170  shows that for the current serving cell (e.g., eNB  122 A), there is a greater than 10% SRVCC handover call failure, the pre-B 2  threshold may be set such that there is a greater likelihood that there will be an attempt to hand the call over to the IWLAN  224 . In contrast, if the failure rate is relatively low (e.g., less than 1%), the pre-B 2  threshold will be set such that it is less likely that a call handover to the IWLAN  224  will occur. Those skilled in the art will understand that the failure rates are only exemplary and different thresholds for failure rates and different types of parameters may be used to set the B 2  threshold. 
     In  225 , the baseband processor of the UE  110  may perform measurements on neighboring cells. At any time during the measurement cycle, the radio conditions may trigger a B 2  event in  260  (e.g., the received signal code power (“RSCP”) of an inter-RAT neighbor is better than a threshold value). However, as described above, prior to the radio conditions triggering a B 2  event, radio conditions may satisfy the pre-B 2  threshold as shown in  230 . That is, while performing the neighboring cell measurements, the UE  110  is constantly comparing the measurements against the pre-B 2  threshold in  230  such that the pre-B 2  action may occur prior to the measurements triggering the B 2  event in  260 . 
     In  230 , if the target neighboring cell satisfies the threshold (e.g., has an RSCP value that satisfies the pre-B 2  threshold calculated in  220 ), then the UE  110  in  235  may notify the eNB  122 A to determine if an iWLAN handover can be triggered on a locally available WiFi network (e.g., iWLAN  124 ). If no target neighboring cell has an RSCP value equal to the pre-B 2  threshold, then the UE  110  may return to  225  and continue performing neighbor cell measurements. 
     In  240 , the eNB  122 A may utilize the IRAT module  125  to evaluate the current WiFi conditions (e.g., the signal strength, historical Real-time Transport Protocol (“RTP”) packet loss in downlink/uplink, etc.) of any available WLANs in the vicinity of the UE  110 . Furthermore, the eNB  122 A may also consider device motion and whether the current WiFi source may be used to perform a handover to iWLAN. Accordingly, during  240 , the IRAT module of the eNB  122 A may recommend the use of WiFi for the UE  110  if there is sufficient WiFi signal strength and an iWLAN handover is supported by the UE  110 . If the IRAT module  125  does not recommend WiFi usage to the UE  110 , then the UE  110  may return to  225  and continue performing neighbor cell measurements. As will be described below, the IRAT evaluation functionalities may be implemented within the exemplary UE  110 . 
     In  245 , the UE  110  may attempt an iWLAN handover to transfer the current call in progress from VoLTE to WiFi. If the iWLAN handover is successful, in  250  the UE  110  continues the call over the WiFi network (e.g., IWLAN  124 ) and thus avoids the need to use an SRVCC handover to an alternative RAT (e.g., a legacy 2G/3G RAN). However, if the iWLAN handover is unsuccessful, in  255  the UE  110  may record and store the reason for the handover failure for future assessment. This information may also be reported to the diagnostic server  170  and stored as further historical data for use during a subsequent VoLTE call and handover process. 
     Returning to  225 , if the iWLAN handover is not successful, the UE  110  will continue to make the neighboring cell measurements and a B 2  event may be triggered by the measurements. In  260 , the UE  110  triggers and reports a B 2  event based on either the neighbor measurements performed in  225  or the failed iWLAN handover in  255  (e.g., the B 2  threshold may be satisfied during the time that the UE  110  is attempting to handover to the IWLAN  224 ). As noted above, a B 2  event is triggered when the radio conditions at the serving cell become worse than a first threshold and the conditions at an IRAT neighboring cell become better than a second threshold (e.g., the LTE RAN  122  is likely to drop the VoLTE call and the legacy RAN  120  has better radio conditions). The B 2  event may be reported to the eNB  122 A, wherein the eNB  122 A may request a Mobility Management Entity (“MME”) for a handover request. Accordingly, the MME may complete the resource reservation with a Mobile Switching Center (“MSC”) and legacy RAN  120  infrastructure. The MME and MSC may be functionalities that are implemented by the cellular core network  130 . 
     In  265 , once resources have been reserved, the eNB  122 A may transmit a handover from evolved UMTS Terrestrial Radio Access (“E-UTRA”) command (e.g., MobilityFromEUTRACommand) with CS bearers required to set up the call on a legacy RAN  120 . However, if the E-UTRA command is not available, instead of causing the call to fail, in  295  the eNB  122 A may check if the iWLAN handover failure was temporary and re-attempt the iWLAN handover by returning to  235 . Thus, an SRVCC failure may be avoided. 
     Even if the E-UTRA command is available in  265 , the actual CS bearer required for the SRVCC call may not be available. Experience with some network implementations shows that certain networks may not send CS bearers to the UE  110 , but only the handover from E-UTRA command to perform a PS handover. The availability of the CS bearer is determined in  270 . In  270 , if no CS bearers are available in the legacy RAN  120 , the handover to the legacy RAN  120  may fail in  290 . However, the exemplary embodiments allow for the call to potentially be continued because, in  295 , the eNB  122 A may check if the iWLAN handover failure was temporary and again, re-attempt the iWLAN handover by returning to  235 . Since IMS features may not be deployed over legacy RANs, the IRAT evaluation in  235  (and thus iWLAN handover in  250 ) may be activated when the UE  110  has sufficient WiFi coverage. Therefore, this IRAT evaluation in  235  may save the call in progress that would have been otherwise dropped in the absence of CS bearers on the legacy RAN  120 . 
     To finish with the flow in  FIG. 2 , if CS bearers are available in a legacy RAN  120  in  270 , the call setup may continue on a legacy RAN  120 , such as Wideband CDMA (“WCDMA”) in  275 . If the UE  110  is able to acquire WCDMA in  275  after receiving the handover from E-UTRA command from an LTE serving system (e.g., MME), the UE  110  may then attempt to complete the handover to UTRA. For instance, the UE  110  may transmit a handoverToUTRANComplete command to a WCDMA cell and attempt to continue the call on WCDMA after setting up radio bearers. In  280 , the UE  110  may determine whether the WCDMA acquisition was successful. If the UE fails to acquire the legacy RAN  120  cell, in  295  the eNB  122 A may check if the iWLAN handover failure was temporary and the IRAT evaluation in  235  (and thus iWLAN handover in  250 ) may be activated when the UE  110  has sufficient WiFi coverage. 
     Thus, it should be seen from this exemplary flow, that there may be multiple manners of continuing the current VoLTE call by a handover to an IWLAN, even if the SRVCC will fail. The first attempt to handover to IWLAN may occur prior to the B 2  threshold being satisfied (e.g., when the pre-B 2  threshold is satisfied). However, there may also be subsequent attempts to handover to IWLAN after the B 2  threshold is satisfied when various failures occur during attempting to connect via the legacy circuit switched network. 
     It should be noted that in the exemplary embodiments, the thresholds were described with reference to thresholds associated with operation of an LTE network, e.g., B 2 , A 2 , etc. Those of skill in the art will understand that this is only exemplary and that the exemplary embodiments may be applied to any packet switched cellular network that may attempt to handover a voice call to a WLAN network, rather than to a legacy circuit-switched network under certain conditions. Thus, the exact nature of the thresholds may be dependent on the particular type of packet switched cellular network. 
       FIG. 3  shows an exemplary method  300  for an enhanced handover mechanism by a mobile device, such as the UE  110 , in a communication with the eNB  122 A and a plurality of wireless networks, such as LTE-RAN  122  and the iWLAN  124 , according to various embodiments described herein. Thus, it is noted that the entirety of method  300  may be performed by the UE  110  of  FIG. 1 , as well as the components of the UE  110 , such as application processors and baseband processors. That is, the processes described above with reference to the method  200  may be performed by various components within the network arrangement  100 . The method  300  shows operations that may be performed by the UE  110  in accomplishing the handover of the method  200 . 
     According to one exemplary embodiment of the method  300 , in  310  the UE  110  may receive historical data from a diagnostic server  170  via the eNB  122 A. As described above, the historical data may be related to the particular serving cell to which the UE  110  is currently attached and the serving cell&#39;s neighboring cells. However, the historical data may also cover a larger geographical area including multiple cells. An example of the types of historical data that the UE  110  may receive is the failure rate for SRVCC handovers, measurement thresholds, etc. Other types of historical data may also be received, for example, the failure rate may be broken down by network load or particular radio conditions, etc. 
     In  320 , the UE  110  may receive or derive location data for the UE  110 . Those skilled in the art will understand that there are any number of manners that a UE may generate or receive location data, including, but not limited to using GPS data, based on triangulation of received signals, or by simply receiving location information from the eNB  122 A. In  330 , the UE  110  may determine a probability of a failed handover during a call based on the historical data and the location data. For example, the UE  110  may determine that in the specific location that the UE  110  is currently in and being attached to the particular serving cell, the network had an SRVCC handover failure rate of 10%. 
     In  340 , the UE  110  may compare the probability of the failed handover to a threshold value. For example, the threshold may be set to an 5% failure rate, meaning that if the probability of failure is above the threshold, the UE  110  should attempt to handover to a WLAN network before attempting an SRVCC handover, while if below the threshold, the UE  110  may default directly to SRVCC handover. Part of the process  340  may also include the calculation of the pre-B 2  threshold as described above based on the historical data and the measurement of the radio conditions that may be used to trigger the IWLAN handover attempt. In the example started above, with a threshold of 5% and a historical failure rate of 10%, the UE  110  will attempt to force a handover to an IWLAN network prior to attempting the SRVCC handover. Thus, in  350 , the UE  110  may initiate a call handover to a wireless local area network, such as the iWLAN  124 , because the probability of the failed SRVCC handover exceeds the threshold value. 
       FIG. 4  shows an exemplary method  400  for an enhanced handover mechanism by a base station, such as the eNB  122 A, in a communication with the UE  110  and a plurality of wireless networks, such as LTE-RAN  122  and the iWLAN  124 , according to various embodiments described herein. Thus, it is noted that the entirety of method  400  may be performed by the eNB  122 A of  FIG. 1 , as well as the components of the eNB  122 A, such as the IRAT module  125 . Similar to the method  300  that may be performed exclusively by the UE  110 , the method  400  shows operations that may be performed exclusively by the eNB  122 A in accomplishing the handover of the method  200 . As should be understood from a comparison of the methods  300  and  400 , there are some processes of accomplishing the handover of method  200  that may be performed by either the UE  110  or the eNB  122 A. 
     According to one exemplary embodiment of the method  400 , in  410  the eNB  122 A may receive historical data from diagnostic server  170 . In  420  the eNB  122 A may receive location data from the UE  110  or calculate a location for the UE based on received signals from the UE  110 . In  430  the eNB  122 A may calculate a pre-threshold value, such as the pre-B 2  threshold, based on the historical data and location data. In  440  the eNB  122 A may transmit the pre-threshold value to the UE  110 . In  450  the eNB  122 A may receive an IRAT evaluation request from the UE  110 . In  460  the IRAT module  125  of the eNB  122 A may evaluate a wireless local area network, such as the iWLAN  124 , based on the location data of the UE  110 . In  470  the eNB  122 A may recommend a WiFi link preference to the UE  110  for a call handover from VoLTE to iWLAN. 
     As noted above, the exemplary UE  110  may support communications over both VoLTE and WiFi. Furthermore the UE  110  may also support handovers of a WiFi call to a VoLTE call as long as a target cell supports VoLTE. According to the exemplary embodiments described herein, the UE  110  may use 3GPP-compliant S2b-based solutions to support handover from a WiFi call to a VoLTE call, and vice versa. 
     The above describes methods for accomplishing a voice call handover from an LTE RAN  122  to an IWLAN  124 . The following describes manners of accomplishing a handover of a voice call from the IWLAN  124  to the LTE RAN  122 . Those skilled in the art will understand that under some circumstances a user of the UE  110  may start a voice call while connected to a WLAN. However, the user may then become mobile and reach the edge of the WLAN, but still wants to maintain the voice call. Legacy networks (e.g., UMTS, CDMA, etc.) may not have quality of service (“QoS”) enabled IMS VoIP services. Therefore, to maintain the call, the UE  110  may only handover from WiFi to VoLTE-capable networks. The UE  110  may perform various operations to increase the likelihood that the active call is maintained by biasing the UE  110  to camp on a cell of an LTE network. 
     During cell re-selection, the UE  110  may camp on the best available cell. Exemplary cell re-selection systems and methods may be enhanced to improve the standby time of the UE  110  as well as the camping cell quality performance. For instance, the UE  110  may use S and R criteria during the cell re-selection process. The S-criteria may include the device-measured quality of the surrounding cells. The R-criteria may include a ranking of each of the cells, wherein the UE  110  may select the best cell as the next serving cell. 
     The UE  110  may utilize any number of inputs during the cell re-selection process. These inputs may include priority and radio link quality. With regards to priority, the wireless network may notify the UE  110  of cell re-selection priority through the use of SIB broadcasts. For instance, SIBS may indicate inter-frequency priority, SIB6 may indicate LTE-WCDMA priority, SIB7 may indicate LTE-GSM priority, etc. With regards to radio link quality, the UE  110  may consider signal strength (RSCP, RSRP, etc.), signal quality (Ec/Eno, RSRQ, etc.). Accordingly, the wireless network may provide various threshold values to allow re-selection using SIB broadcast messages. The UE  110  may trigger a cell re-selection process when the signal strength and/or signal quality of the serving cell meets certain threshold values. 
     Due to the exponential growth in data traffic, carriers are eager to utilize deployed networks as efficiently as possible. Carriers may implement a network controlled idle-mode steering mechanism to steer network traffic to deployed heterogeneous networks. Furthermore, carriers may control network based traffic steering by broadcasting optimal threshold and priority values in various SIB broadcast messages that the UE  110  may use for idle-mode cell re-selection. 
     Current cell re-selection processes do not take into account the state of WiFi coverage for the UE  110  for a possible handover of a WiFi call (e.g., iWLAN  124 ). In the case of cellular preferred carriers, the UE  110  may only camp on WiFi when cell coverage is marginal or non-existent. However, when cellular coverage is marginal, the UE  110  is more likely to camp on a legacy RAN  120  (e.g., GSM or UMTS) since the relative radio conditions on the legacy RAT is typically better than those on the LTE-RAN  122 . If the user of the UE  110  initiates a voice call over a WiFi network and then travels beyond the coverage, the UE  110  will not be able to handover the call in progress from WiFi to cellular. Thus, the call will then be dropped. 
     In order to address these problems, the exemplary embodiments described herein may consider the IMS registration state and/or the state of the WiFi call during the cell re-selection process. Furthermore, the exemplary embodiments described herein may also consider the state of WiFi call of several devices camped on an eNB or Radio Network Controller (“RNC”) during the network steering process. 
       FIG. 5  shows an exemplary method  600  for enhanced cell re-selection by a mobile device, such as the UE  110 , in a communication with the eNB  122 A and a plurality of wireless networks, such as LTE-RAN  122  and the iWLAN  124 , according to various embodiments described herein. Thus, it is noted that the entirety of method  600  may be performed by the UE  110  of  FIG. 1 , as well as the components of the UE  110 , such as application processors and baseband processors. 
     Thus, the embodiment of  FIG. 5  may be a cell reselection process that is controlled by the UE  110 . The method of  FIG. 5  may include two specific scenarios where the UE  110  will be biased for the cell reselection of an LTE RAN  122  cell over the cell of a legacy RAN  120 . The first scenario is when there is an active WiFi call. As described above, if there is an active WiFi call, the only way to preserve the active call if the user leaves the coverage of the WiFi network is to pass the call to another packet switched network, e.g., an LTE network. If the UE  110  camps on a legacy RAN  120  cell, and the user leaves the WiFi coverage area, the call will be dropped. 
     The second scenario is when the UE  110  is IMS registered over WiFi. Again, because the UE  110  is IMS registered, it is more likely that the first scenario may occur, therefore, even if a call is not currently active, the UE  110  should prefer reselection to LTE to avoid dropped calls. For example, in the second scenario, the UE  110  may be IMS registered and currently connected to the iWLAN  124 . However, while moving within the coverage area of the iWLAN  124 , the UE  110  may move to a location where, if having to switch to a cellular network, the UE  110  is now outside the coverage area of the previous cell (e.g., LTE RAN  122  cell or legacy RAN  120  cell) to which it was connected. Thus, the UE  110  may perform a cell reselection for the cellular network while the UE remains connected to the iWLAN  124 . Thus, if the cell reselection were to select a cell of the legacy RAN  120 , and the UE  110  later started an active WiFi call, the WiFi call would be dropped when handing over to cellular. On the other hand, if the cell reselection procedure selected a cell of the LTE RAN  122 , the later connected active WiFi call would be transferred to the LTE RAN  122  upon handover. Thus, even if the UE  110  does not have a currently active call, because it is IMS registered, there is a higher likelihood that the UE  110  may have an active call when cellular handover is required. 
     According to one exemplary embodiment of the method  600 , it is considered that the UE  110  is currently connected to the iWLAN  124 . In  610  the UE  110  may determine if there is an active WiFi call (the first scenario). If there is no active WiFi call, in  630 , the UE  110  may determine if the UE  110  is currently IMS registered over WiFi (the second scenario). Those skilled in the art will understand that if the UE  110  is IMS registered, the UE  110  will have a saved context indicating the IMS registration. If there is currently an active WiFi call ( 610 ) or the UE  110  is IMS registered ( 630 ), the method continues to  620  where the UE  110  biases the cell reselection to LTE. As described above, the UE  110  will bias the cell reselection to LTE because the UE  110  prefers that an active call not be dropped during the reselection and handover process. Thus, by biasing the cell reselection to LTE, it is less likely that a packet switched WiFi call will be dropped because the call may be handed over to the packet switched LTE RAN  122 , whereas the circuit switched legacy network  120  would not be able to continue the WiFi call. 
     After the cell reselection is biased to LTE in  620 , in  640  the UE  110  determines if a cell reselection is required. Those skilled in the art will understand that there are many different reasons for the cell reselection procedure to be initiated (e.g., based on cell measurements). If the cell reselection procedure is initiated in  640 , in  660  the UE  110  should select an LTE cell on which to camp. Those skilled in the art will understand that while the cell reselection procedure is biased to the LTE RAN  122 , it is not a guarantee that the LTE RAN  122  will be selected. For example, the LTE bias means that if there is an LTE RAN  122  cell available that meets the minimum requirements for communicating with the UE  110 , the LTE RAN  122  cell will be selected. However, there may be instances, when there is no available LTE RAN  122  cell. In these instances, the UE  110  will camp on a cell of the legacy RAN  120 , if available. 
     In  670 , if the UE  110  is leaving the coverage area of the iWLAN  124 , the UE  110  may initiate a call handover from the iWLAN  124  to the LTE RAN  122  when the UE  110  has an active WiFi call (e.g., is in the first scenario). As described above, this first scenario may occur before or after the cell reselection procedure. Thus, the biasing of the cell reselection to the LTE RAN  122  preserves the WiFi call when the UE  110  leaves the WiFi coverage area. 
     Returning to  630 , if there is neither an active call (no first scenario) nor is the UE  110  IMS registered over WiFi (no second scenario) and a cell reselection procedure is required in  650 , the UE  110  will perform the standard cell reselection procedure. That is, the cell reselection procedure may not be biased to the LTE RAN  122 . Those skilled in the art will understand that the standard cell reselection procedure may encompass many different methods for cell reselection and any of these methods may be used. The point being that in the standard cell reselection procedure there is no biasing toward the LTE RAN  122  because of an active WiFi call or IMS registration. 
       FIG. 6  shows an exemplary method  700  for enhanced network traffic steering by a base station, such as the eNB  122 A, in a communication with the UE  110  and a plurality of wireless networks, such as LTE-RAN  122  and the iWLAN  124 , according to various embodiments described herein. Thus, it is noted that the entirety of method  700  may be performed by the components of the LTE RAN  122 , including the eNB  122 A. 
     According to one exemplary embodiment of the method  700 , in  710  the eNB  122 A may determine the number (if any) of UEs that are currently are camped on the eNB  122 A that have active WiFi calls. It should be understood that the LTE RAN  122  (and therefore the eNB  122 A) may have a direct or indirect connection to the iWLAN  124  to make this determination. For example, the LTE RAN  122  may connect to the iWLAN  124  via the cellular core network  130  or via the Internet  140  to query the iWLAN  124  if any of the UEs that are currently connected to the eNB  122 A have active WiFi calls. In another example, the LTE RAN  122  may query the IMS  150  to determine if any of the UEs that are currently connected to the eNB  122 A have active WiFi calls. It should be noted that the eNB  122 A and the LTE RAN  122  will have a list of UEs (based on a unique identifier such as IMSI, MAC address, etc.) that are currently connected to the eNB  122 A. In  720 , the eNB  122 A will determine the number of UEs that are currently camped on the eNB  122 A that are IMS registered via WiFi. This determination in  720  may be performed in the same manner as was described above for determining the active WiFi calls in  710 . 
     In  730 , the eNB  122 A will determine the percentage of connected UEs that meet the criteria, e.g., that have active WiFi calls and/or are WiFi IMS registered. It should be noted that the percentage may be determined in any number of manners. For example, the percentage may be based on the number of UEs meeting the first scenario compared to the total number of UEs connected to the eNB, the number of UEs meeting the second scenario compared to the total number of UEs connected to the eNB, a combined number of UEs meeting the first scenario and second scenario compared to the total number of UEs connected to the eNB, etc. In addition, while the exemplary embodiments are described with reference to a percentage value, the value may also be expressed in other mathematical terms such as a ratio, etc. In  740 , the eNB  122 A determines if the percentage determined in  730  exceeds a threshold value. This threshold value may be set based on any number of factors. In one exemplary embodiment, the threshold may be set to a percentage value of 20%. However, this is only exemplary and any other threshold may be used. 
     If the percentage exceeds the threshold in  740 , this means that the eNB  122 A should bias the network steering priority to LTE. As described above, the UEs will ultimately perform the cell reselection procedure, but the eNB  122 A may bias the UEs selection by setting priorities for the cell reselection. When the percentage is high (e.g., above the threshold), the eNB  122 A may determine that it the UEs should be biased toward selecting the LTE RAN  122  for the reasons that were described above (e.g., to avoid dropping WiFi calls when handing over from WiFi to cellular). Thus, if the percentage exceeds the threshold in  740 , the eNB  122 A will set the network steering priority to LTE in  760 . This will cause the eNB  122 A to broadcast SIB messages indicating this priority to all the UEs that are currently camped on the eNB  122 A in  770 . Thus, the eNB  122 A may bias the connected UEs to prefer reselection to cells of the LTE RAN  122 . 
     If the percentage does not exceed the threshold in  740 , the eNB  122 A may set the network steering priority in a standard manner. Again, the standard manner may encompass different methods of setting the network steering priority, but it does not include biasing toward LTE because of active WiFi calls and/or WiFi IMS registration. Similar to the above described network steering method that biases toward LTE, the eNB  122 A will also broadcast SIB messages indicating the standard priority in  770 . 
       FIG. 7  shows an exemplary UE  800  according to various embodiments described herein. The UE  800  may represent any electronic device that is configured to perform wireless functionalities and may be representative of the UE  110  depicted in  FIG. 1 . Accordingly, the UE  800  may be a portable device such as a smartphone, a tablet, a phablet, a laptop, a wearable, etc. In another example, the UE  800  may be a client stationary device such as a desktop terminal. The UE  800  may be configured to perform cellular and/or WiFi functionalities. The UE  800  may include a processor  805 , a memory arrangement  810 , a display device  815 , an input/output (I/O) device  820 , an IRAT module  825  a transceiver  830 , and other components  835 . The other components  835  may include, for example, an audio input device, an audio output device, a battery, a data acquisition device, ports to electrically connect the UE  800  to other electronic devices, etc. 
     The processor  805  may be configured to execute a plurality of applications of the UE  800 . It should be noted that the above noted applications each being an application (e.g., a program) executed by the processor  805  is only exemplary. The functionality associated with the applications may also be represented as a separate incorporated component of the UE  800  or may be a modular component coupled to the UE  800 , e.g., an integrated circuit with or without firmware. In addition, in some UEs, the functionality described for the processor  805  is split among two processors, a baseband processor and an applications processor. The exemplary embodiments may be implemented in any of these or other configurations of a UE. 
     The memory  810  may be a hardware component configured to store data related to operations performed by the UE  800 . Specifically, the memory  810  may store data related to various applications. The display device  815  may be a hardware component configured to show data to a user while the I/O device  820  may be a hardware component that enables the user to enter inputs. It should be noted that the display device  815  and the I/O device  820  may be separate components or integrated together such as a touchscreen. 
     The IRAT module  825 , as noted above, may be used to evaluate WiFi conditions of a wireless network, such as the iWLAN  124 . Similar to the IRAT module  125  of the eNB  122 A of  FIG. 1 , the IRAT module  825  may implement IRAT evaluation functionalities on the UE  800 . According to this embodiment, the IRAT module  825  will allow the UE  800  to decide between operating over the WiFi network versus operating over a cellular network. While the IRAT module  825  may reside on the UE  800 , a SRVCC (e.g., LTE to CS) handover decision may still be implemented by an eNodeB (e.g., eNB  122 A). For instance, the UE  800  may be responsible for sending measurement reports to eNB  122 A, the UE  800  may also have the option to initiate WiFi handover before the network triggers SRVCC handover if the UE  800  knows that a SRVCC handover is most likely going to fail. The UE  800  may determine the probability of SRVCC handover failure based on location, B 2  threshold and historical information in the same manner as described above wherein the eNB  122 A performed this functionality. 
     The transceiver  830  may be a hardware component configured to transmit and/or receive data. That is, the transceiver  830  may enable communication with other electronic devices directly or indirectly through one or more networks based upon an operating frequency of the network. The transceiver  830  may operate on a variety of different frequencies or channels (e.g., set of consecutive frequencies) that are related to the VoLTE call functionality. Thus, one or more antennas (not shown) coupled with the transceiver  830  may enable the transceiver  830  to operate on the LTE frequency band as well as over a WiFi network. 
     It may be noted that the exemplary embodiments are described with reference to the LTE and LTE-Advanced communication system. However, those skilled in the art will understand that the exemplary embodiments may be applied to managing dynamic dormancy timers within any wireless communication schemes including those having different characteristics from the LTE scheme. 
     It will be apparent to those skilled in the art that various modifications may be made in the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Metadata:
Filing Date: 20160527
Publication Date: 20190305
Grant Date: 20190305
Priority Date: 20150930
Inventors: SINGH, AJOY K.
BHATTACHARJEE, DEEPANKAR
CHAUGULE, RAJ S.
VERMA, SANJAY K.
BYUN, KWANGHO
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W48/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W84/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W48/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W84/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/16", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/14", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W48/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/16", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/0022", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0083", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/245", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W84/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/1446", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/00226", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/008375", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0066", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/008375", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/008375", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/1446", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/00226", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/00226", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/1446", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 58282153