Patent Description:
Mobile devices, such as mobile phones, wireless modems, tablets, or any other device with a processor that communicates with other devices through wireless signals are becoming increasingly popular and are used more frequently. Subscribers using such mobile devices in a cellular/wireless communication network are typically authenticated by the wireless communication network before being granted access to initiate and/or receive calls and transmit and/or receive data.

During use, mobile devices often move relative to access points such that handing off connections between access points is generally useful to maintain active network connection, as for example described in <CIT>; <CIT>; or <CIT>. Handovers typically involve disconnecting from a first access point prior to connecting to a second access point. During a handover time period, mobile devices cannot send data either over the first wireless connection (because the first wireless connection is terminated) nor over the second wireless connection (because the second wireless connection has not yet been established).

Embodiments and aspects that do not fall within the scope of the claims are merely examples used for explanation of the invention. Wording such as "may" and "for example" used in the description in conjunction with features of the independent claims should not be interpreted to mean that those features are merely optional.

In the following description, specific details are given to provide a thorough understanding of the described implementations. However, it will be understood by one of ordinary skill in the art that the implementations may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the implementations in unnecessary detail. In other instances, well-known circuits, structures and techniques may be shown in detail in order not to obscure the implementations.

" Any implementation or embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or implementations. Likewise, the term "embodiments" does not require that all embodiments include the discussed feature, advantage or mode of operation. The term "user equipment" (UE) as used herein is meant to be interpreted broadly. For example, a "user equipment" or "UE" may include a mobile phone, a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a pager, a wireless modem, a personal digital assistant, a personal information manager (PIMs), personal media players, client devices, subscriber devices, tablet computers, laptop computers, a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, , an entertainment device, a medical device, industrial equipment, actuator/sensor component, automotive component, metering equipment, IoE/IoT devices, and/or other mobile communication/computing devices which communicate, at least partially, through a wireless or cellular network. The term "access node" is also meant to be interpreted broadly, and includes, for example, an evolved Node B (ENB), a base station, a base transceiver station, a radio base station, a radio transceiver, a basic service set (BSS), an extended service set (ESS), a network access point, and/or a network connectivity node that may be part of a radio access network and provides wireless network connectivity to one or more UEs.

There is a need for methods, apparatus, and/or systems that improve the handover procedure to reduce, minimize or eliminate the lack of data access by a mobile device (e.g., UE) during the handover period.

A technique is disclosed to minimize service interruption of a wireless user equipment device during a handover from one access node to another access node by maintaining dual active connections during the handover. Upon initiating the handover, an initial/first connection with a first access node is maintained while establishing a second connection with a second access node. The user equipment device can receive data over the first connection and second connection during the handover. The first connection may be terminated (by the user equipment device or by timing out due to inactivity) after the handover is completed.

<FIG> is a diagram illustrating an exemplary next generation communication network architecture, such as an evolved packet system (EPS) <NUM>, according to some aspects/embodiments. The EPS <NUM> may include one or more user equipment (UE) <NUM>, a Radio Access Network (RAN) <NUM> (e.g., Evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRAN)), an Evolved Packet Core (EPC) <NUM>, a Home Subscriber Server (HSS) <NUM>, and a Packet Switched Network <NUM>. As shown, the EPS <NUM> provides packet-switched services, however, as those skilled in the art will readily appreciate, the various concepts presented throughout this disclosure may be extended to networks providing circuit-switched services.

The RAN <NUM> may include one or more access nodes A <NUM> and B <NUM>. Additionally, other access nodes C <NUM>, coupled to other RANs and/or other MMEs may also serve to provide connectivity to the UE <NUM>. As the UE <NUM> moves, its wireless connection service with the first node A <NUM> may be handed over to another access node B <NUM> and/or C <NUM> (e.g., within the same RAN or different RANs).

In one example, the first access node A <NUM> may be connected (or communicatively coupled) to the second access node B <NUM> via a backhaul interface X2. The first access node A <NUM> may serve as an access point to the EPC <NUM> for the UE <NUM>.

The first access node <NUM> may be connected by an interface S1 to the EPC <NUM>. The EPC <NUM> may include a Mobility Management Entity (MME) <NUM>, other MMEs <NUM>, a Serving Gateway (SGW) <NUM>, and a Packet Data Network (PDN) Gateway <NUM>. The MME <NUM> may be the control node that processes signaling between the UE <NUM> and the EPC <NUM>. All user IP packets may be transferred through the Serving Gateway (SGW) <NUM>, which itself is connected to the PDN Gateway <NUM>. The PDN Gateway <NUM> may provide the UE internet protocol (IP) address allocation as well as other functions. The PDN Gateway <NUM> may be connected to the packet switched data network <NUM>. The packet switched data network <NUM> may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), and a PS Streaming Service (PSS).

The access nodes A <NUM> and B <NUM> typically communicate with each other via an "X2" interface. The access nodes A <NUM> and B <NUM> communicate with the EPC <NUM> (including the MME <NUM> and SGW <NUM>) via an "S1" interface.

In existing wireless communication networks, such as a <NUM> network or Long Term Evolution (LTE) network, Non-Access Stratum (NAS) protocols form the highest stratum of the control plane between the user equipment (UE) <NUM> and the MME <NUM>. NAS protocols support mobility of the UE <NUM> and the session management procedures to establish and maintain IP connectivity between the UE <NUM> and a PDN gateway <NUM>.

In one example, the EPS <NUM> may utilize an EPS Session Management (ESM) protocol which provides procedures for the handling of EPS bearer contexts. Together with the bearer control provided by the Access Stratum, it provides the control of user plane bearers. The transmission of ESM messages is suspended during EMM procedures except for the attach procedure.

In one example, the EPS <NUM> may utilize an EPS Mobility Management (EMM) protocol which provides procedures for the control of mobility when the User Equipment (UE) uses the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN). It also provides control of security for the NAS protocols.

In existing EPS systems, a UE is supported by a single MME at any one time. When a handover occurs across MME boundaries (i.e., from a first MME to a second MME), MME relocation of the UE is required. During this handover, the UE may be left without a data connection. For instance, as the UE switches from a first wireless connection with a first access node (coupled to a first MME) to a second wireless connection with a second access node (coupled to a second MME), there is a period of time in which the first wireless connection is terminated but the second wireless connection is not yet established.

In next generation networks and according to some aspects/embodiments, as the MME functionality is moved closer to the access nodes, the MME relocation procedures may occur much more frequently. Consequently, loss of connectivity for UE devices may become more noticeable. As described herein, a new procedure is disclosed to optimize handover performance by using dual active connections with different access nodes (e.g., served by different MMEs) to allow the UE to maintain a data connection during a handover.

As part of providing service to a UE, an MME context per link/connection is setup with an access node for each UE being served. Such MME context is setup between the MME and access node. An MME context may include both an EPS Mobility Management (EMM) context and one or more EPS Session Management (ESM) contexts associated with the UE. An MME context applies to one or more radio access technologies (RATs), e.g., a multi-access MME context including wireless local area network (WLAN) and LTE. The EMM context for a UE is authenticated for access at the network provisioning the credentials used by the UE for attachment (home or visited AAA for roaming), i.e., the access credentials. The access credential function serves to enable service to the UE to be established securely and there may not necessarily be a billing relationship between the access credential provider and the serving network. One or more ESM contexts, where each ESM context is associated with one or more APNs, may be used to host the ESM (session management) functions for each service.

Some implementations may use more than one MME context simultaneously on a single connection to an access node. The access node may merge or reconcile the two MME contexts for a UE at the RAN and figure out mobility, conflicts, etc., between the two MME contexts. As part of establishing a connection between a UE and access node, a single UE context is typically defined at the access node for the UE. One MME context implies only one identifier, e.g., global unique temporary identifier (GUTI), for the UE context at an access node.

A UE may have multiple MME contexts active simultaneously when it has multiple links/connections active simultaneously. For example, the UE may be connected over two links to separate access nodes that are not served by the same MME.

While <FIG> illustrates an exemplary network in which one or more aspects and features may be implemented, these features may also be implemented on various types of networks, including subscriber networks, public data network (PDN) networks, wireless networks, etc..

<FIG> is a block diagram illustrating a first example of a handover using dual active connections within a single radio access network (RAN-A) <NUM> with a common mobility management entity (MME) <NUM> and using a common serving gateway (SGW) and PDN gateway (PGW) <NUM> according to some aspects/embodiments. In this example, a single authentication, authorization, and accounting (AAA) server <NUM> is used by the UE device <NUM> (i.e., one subscription is used by the UE device <NUM>). The UE device <NUM> may include a transceiver circuit capable of receiving from two different connections, such as two separate receiver circuits or a single receiver circuit that can be shared (e.g., using multiplexing or timeslots) to receive from (and transmit to) two distinct connections. In this example, a handover of the UE device <NUM> occurs from a first connection via a first access node A <NUM> and to a second connection via a second access node B <NUM> while utilizing an X2 interface between the first access node A <NUM> and second access node B <NUM>.

<FIG> is a flow diagram illustrating one example of how a handover using the X2 interface between access nodes may be implemented using dual active connections for a UE device within the network environment of <FIG> according to some aspects/embodiments. The UE device <NUM> may have previously established a first connection or link (e.g., a radio bearer) with the serving first access node A <NUM>. The UE device <NUM> may be configured for a dual active connection handover. Upon the occurrence of a triggering event <NUM> (e.g., receipt of other access node pilot/advertisement, periodic scanning for new access nodes, request from currently serving access node, etc.), the UE device <NUM> may provide a measurement report <NUM> (e.g., signal strength measurement, error packet count, etc.) to a currently serving access node A <NUM>. The serving access node A <NUM> may make a decision <NUM> (e.g., based on the measurement report <NUM>) on whether a handover is appropriate. If the access node A <NUM> decides to initiate a handover of connectivity service for the UE device <NUM> to a different second access node B <NUM>, a handover request <NUM> is sent to the second access node B <NUM> which decides on accepting the request (e.g., as part of admission control <NUM>). If the second access node B <NUM> determines to accept the handover request <NUM>, it may send a handover command <NUM> to the first access node A <NUM>. Upon receipt of the handover command <NUM>, the first access node A <NUM> may send a connection reconfiguration request <NUM> to the UE device <NUM>. In response, the UE device <NUM> may send a connection reconfiguration complete message <NUM> to the first access node A <NUM>, indicating that the UE device <NUM> shall start the handover to the second access node B <NUM>. The first access node A <NUM> may then send a handover complete message <NUM> to the second access node B <NUM>.

Upon performing a synchronization with the new cell <NUM> (e.g., the cell for the second access node B <NUM>) the UE device <NUM> may establish a second connection (with the second access node B <NUM>) by sending a random access preamble <NUM> to the second access node B <NUM> and, in reply, receiving a random access response <NUM>. At this point, the UE device <NUM> may have two concurrent connections, i.e., the first connection with the first access node A <NUM> and the second connection with the second access node B <NUM>.

During this handover stage, the first access node A <NUM> may buffer packets to the UE device <NUM> and delivers in-transit packets <NUM> to the second access node B <NUM>. For instance, the first access node A <NUM> may send an status transfer message <NUM> (e.g., to indicate packets for the UE device <NUM> are being forwarded) to the second access node B <NUM> and then a data forwarding message <NUM> including the in-transit packets intended for the UE device <NUM>. That is, the packets arriving at the first access node A <NUM> for the UE device <NUM> during the handover procedure may be forwarded to the second access node B <NUM> which can then deliver them to the UE device <NUM>. Consequently, the second access node B <NUM> may send downlink data packets <NUM> to the UE device <NUM> while the UE device <NUM> may send uplink data packets <NUM> to the second access node B <NUM>, which then forwards <NUM> them to the PGW/SGW <NUM>.

Note that during this handover, the forwarding of in-transit packets may be in addition to the first access node A <NUM> sending the packets directly to the UE device <NUM>. The UE device <NUM> may simply discard any duplicate packets received (e.g., packet identifiers may be used to compare packets received from the first access node A <NUM> and the second access node B <NUM> and discard duplicate packets).

The second access node B <NUM> may initiate a user plane switch (e.g., downlink path for the UE device <NUM>) by sending a switch request <NUM> to the MME <NUM>. This notifies the MME <NUM> that packets to the UE device <NUM> should be forwarded to the second access node B <NUM> instead of the first access node A <NUM>.

In turn, the MME <NUM> may send a modify bearer request <NUM> to the PGW/SGW <NUM>. This causes the PGW/SGW <NUM> to switch the downlink path <NUM> for the UE device <NUM> and send an end marker <NUM> to the first access node A <NUM>. The first access node A <NUM> may forward this end marker <NUM> to the second access node B <NUM> to indicate that the second access node B <NUM> should takeover downlink communications for the UE device <NUM>. Consequently, the second access node B <NUM> may transmit both uplink and downlink packet data <NUM> for the UE device <NUM>. The PGW/SGW <NUM> may also send a modify bearer response <NUM> to indicate that the bearer for the UE device <NUM> has been successfully updated. After the last buffered packet <NUM> has been forwarded by the first access node A <NUM> to the UE device <NUM>, the first access node A <NUM> may send a connection release message <NUM> to the UE device <NUM> to terminate the first connection. Additionally, the first access node A <NUM> may send a UE context release request <NUM> to the MME <NUM> and receives a UE context release complete <NUM> in response. Then, the second access node B <NUM> becomes the only serving node and the dual active handover is completed.

In traditional single active handover, the user plane is disconnected between the connection reconfiguration complete message <NUM> and the packet data messaging <NUM>. However, in dual active handover, the interruption can be avoided by having the first access node A <NUM> bi-casting cached downlink packet data to the UE device <NUM> and the second access node B <NUM>. The second access node B <NUM> forwards the received packet data to the UE device <NUM>. The UE device <NUM>, due to its dual active capabilities, is able detect and dispose of duplicate packets that may be received.

If an X2 interface is not available between the first access node A <NUM> and the second access node B <NUM>, the handover can be performed via an S1 interface.

<FIG> is a flow diagram illustrating one example of how a handover using an S1 interface between access nodes and an MME and SGW/PGW may be implemented using dual active connections for a UE device within the network environment of <FIG> according to some aspects/embodiments. The UE device <NUM> may have previously established a first connection with the serving first access node A <NUM>. The UE device <NUM> may be configured for a dual active connection handover. Upon the occurrence of a triggering event <NUM> (e.g., receipt of other access node pilot/advertisement, periodic scanning for new access nodes, request from currently serving access node, etc.), the UE device <NUM> may provide a measurement report <NUM> (e.g., signal strength measurement, error packet count, etc.) to a currently serving access node A <NUM>. The serving access node A <NUM> may make a decision <NUM> (e.g., based on the measurement report <NUM>) on whether a handover is appropriate. If the access node A <NUM> decides to initiate a handover of connectivity service for the UE device <NUM> to a different second access node B <NUM>, a handover required message <NUM> is sent to the MME <NUM>. The MME <NUM> may then send a handover request message <NUM> to the second access node B <NUM>. Upon receipt of the handover request <NUM>, the second access node B <NUM> may perform admission control <NUM> which may result in a handover request acknowledge <NUM> being sent to the MME <NUM>. If so, the MME <NUM> may send a handover command <NUM> to the first access node A <NUM>.

Upon receipt of the handover command <NUM>, the first access node A <NUM> may send a connection reconfiguration request <NUM> to the UE device <NUM>. In response, the UE device <NUM> may send a connection reconfiguration complete message <NUM> to the first access node A <NUM>, indicating that the UE device <NUM> shall start the handover to the second access node B <NUM>.

During this handover stage, the first access node A <NUM> may buffer packets to the UE device <NUM> and delivers in-transit packets <NUM> to the second access node B <NUM>. For instance, the first access node A <NUM> may send an access node status transfer message <NUM> (e.g., to indicate packets for the UE device <NUM> are being forwarded) to the MME <NUM>. In turn, the MME <NUM> may send an access node status transfer message <NUM> to the second access node B <NUM>. The first access node A <NUM> may forward data packets <NUM>, including the in-transit packets intended for the UE device <NUM>, to the second access node B <NUM>. That is, the packets arriving at the first access node A <NUM> for the UE device <NUM> during the handover procedure may be forwarded to the second access node B <NUM> which can then deliver them to the UE device <NUM>. Consequently, the second access node B <NUM> may send downlink data packets <NUM> to the UE device <NUM> while the UE device <NUM> may send uplink data packets <NUM> to the second access node B <NUM>, which then forwards <NUM> them to the PGW/SGW <NUM>.

The second access node B <NUM> may send a handover notify message <NUM> to the MME <NUM>. This may indicate to the MME <NUM> that packets to the UE device <NUM> should be forwarded to the second access node B <NUM> instead of the first access node A <NUM>.

In turn, the MME <NUM> may send a modify bearer request <NUM> to the PGW/SGW <NUM>. This causes the PGW/SGW <NUM> to switch the downlink path <NUM> for the UE device <NUM> and send an end marker <NUM> to the first access node A <NUM>. The first access node A <NUM> may forward this end marker <NUM> to the second access node B <NUM> to indicate that the second access node B <NUM> should takeover downlink communications for the UE device <NUM>. Consequently, the second access node B <NUM> may transmit both uplink and downlink packet data <NUM> for the UE device <NUM>. The PGW/SGW <NUM> may also send a modify bearer response <NUM> to indicate that the bearer for the UE device <NUM> has been successfully updated.

After the last buffered packet <NUM> has been forwarded by the first access node A <NUM> to the UE device <NUM>, the first access node A <NUM> may send a UE context release request <NUM> to the MME <NUM>. In response, the first access node <NUM> may receive a UE context release complete <NUM> from the MME <NUM>. The first access node A <NUM> may then send a connection release message <NUM> to the UE device <NUM> to terminate the first connection. Then, the second access node B <NUM> becomes the only serving node and the dual active handover is completed.

<FIG> is a block diagram illustrating a second example of a handover using dual active connections across RAN constellations <NUM> and <NUM> with mobility management entity (MME) relocation and using a common serving gateway (SGW) and PDN gateway (PGW) <NUM> according to some aspects/embodiments. In this example, a single authentication, authorization, and accounting (AAA) server <NUM> is used by a UE <NUM> (i.e., one subscription is used by the UE <NUM>). However, the handover occurs from a first access node A <NUM> in a first radio access network (RAN-A) <NUM> to a second access node B <NUM> in a second radio access network (RAN-B) <NUM>. The first RAN-A <NUM> may have a corresponding first MME-A <NUM> while the second RAN-B <NUM> may have a corresponding second MME-B <NUM>. A common SGW/PGW gateway <NUM> is shared by the first RAN-A <NUM> and second RAN-B <NUM>. The UE <NUM> may include a transceiver circuit capable of receiving from two different connections, such as two separate receiver circuits or a single receiver circuit that can be shared (e.g., using timeslots) to receive from (and transmit to) two distinct connections. In this example, a handover of the UE device <NUM> occurs from a first connection via the first access node <NUM> and to a second connection via the second access node <NUM>.

<FIG> (comprising <FIG> and <FIG>) is a flow diagram illustrating one example of how a handover between access nodes on different RANs with MME relocation and a common SGW/PGW may be implemented using dual active connections for a UE device within the network environment of <FIG> according to some aspects/embodiments. The UE device <NUM> may have previously established service <NUM> with the first access node A <NUM>, first MME-A <NUM>, and PGW/SGW <NUM>. This may include establishing/obtaining a first connection with the serving first access node A <NUM> while using a first MME-A <NUM> and the SGW/PGW <NUM> while having a first UE context <NUM> at the AAA <NUM>. A dual active connection handover may be triggered <NUM> autonomously by a UE device decision, or the network may indicate (e.g., in an RRC message for the UE device <NUM>) to establish a new connection (e.g., in a CC Handover command with no context).

Upon occurrence of this triggering event <NUM>, the UE <NUM> establishes a second connection with the second access node B <NUM> by sending a random access preamble <NUM> to the second access node B <NUM> and, in reply, receiving a random access response <NUM>. If UE device <NUM> does not need IP address continuity, the UE device <NUM> may establish a new PDN connection with the second access node B <NUM>. The UE device <NUM> may send a handover attachment request <NUM> to the second access node B <NUM>. The second access node B <NUM> sends an initial UE message <NUM> (including the handover attachment request <NUM>) to the second MME-B <NUM> (e.g., the MME serving the second access node B <NUM>). Upon receipt of the initial UE message <NUM>, the second MME-B <NUM> sends an update location request <NUM> to the AAA <NUM> and receives an update location acknowledgement <NUM> from the AAA <NUM>, which includes subscription data for the UE device's second connection. The second MME-B <NUM> then sends an initial UE context setup <NUM> to the second access node B <NUM>. The second access node B <NUM> then sends a connection setup command <NUM> to the UE device <NUM> and, in reply, receives a connection setup complete command <NUM> from the UE device <NUM>. The second access node B <NUM> then sends an initial UE context setup response to the second MME-B <NUM>. The second MME-B <NUM> then sends a notify request <NUM> to the AAA <NUM> and receives a notify response <NUM>. At this point the AAA <NUM> updates the UE context <NUM> for the UE device <NUM> so that it includes the second MME-B and a GUTI2. Meanwhile, the first connection with the first access node A <NUM> remains active and operational.

If the UE device <NUM> decides to move <NUM> its connection to the second access node B <NUM> without PGW/SGW relocation (e.g., it needs IP address continuity), the UE device <NUM> may send a handover connectivity request <NUM> to the second MME-B <NUM> to transfer its connection to the second access node B <NUM> via the second MME-B <NUM>. The second MME-B <NUM> uses in the PGW stored in the subscription data retrieved by the second MME-B <NUM> to create a session request <NUM> that is sent to the PGW/SGW <NUM>. The PGW-SGW sends a session response <NUM> to the second MME-B <NUM>. In turn, the second MME-B <NUM> sends a modify UE context request <NUM> to the second access node B <NUM>. This causes the second access node B <NUM> to send a connection reconfiguration message <NUM> (which includes or acts as a connection response) to the UE device <NUM>. The UE device <NUM> sends a connection reconfiguration complete message <NUM> to the second access node B <NUM> which causes the second access node B <NUM> to send a modify UE context accept message <NUM> to the second MME-B <NUM>. The second MME-B <NUM> sends a notify request <NUM> to the AAA <NUM> and receives a notify response <NUM> in reply.

For the first connection with the first access node A <NUM>, the PGW <NUM> initiates bearer deactivation procedure to release the PDN connection. The PGW/SGW <NUM> notifies the first MME-A that the connection has moved <NUM>. This may include sending a delete session request <NUM> to the first MM-A <NUM>. If there are no remaining PDN connections to the UE device <NUM>, the first MME-A <NUM> performs a detach procedure <NUM> with the UE <NUM> and releases the first connection with the first access node A <NUM>. The first MME-A <NUM> then sends a delete session response message <NUM> to the PGW/SGW <NUM>.

To perform the correct handover procedure, the UE device <NUM> needs to know whether the second access node <NUM> belongs to a different RAN constellation than the first access node A <NUM>. Where network triggered dual active handover is implemented, an rRRC Connection Reconfiguration can include RAN information in the handover command, e.g., a flag indicating the handover is to a different RAN constellation. Where a UE triggered dual active handover is implemented, the UE device <NUM> can use a network identifier to determine that the handover is to a different RAN constellation, e.g., PLMN ID, TAC, or a new identifier such as a constellation identifier may be used to distinguish between RANs.

<FIG> is a block diagram illustrating a third example of a handover using dual active connections across a plurality of RAN constellations <NUM> and <NUM> with mobility management entity (MME) relocation and using separate serving gateways (SGW) and PDN gateways (PGW) <NUM> and <NUM> according to some aspects/embodiments. In this example, a first authentication, authorization, and accounting (AAA) server <NUM> is used by a UE <NUM> (i.e., a first subscription is used by the UE <NUM>) to obtain service via a first connection established with a first access node A <NUM> in a first RAN-A <NUM> using a first MME-A <NUM> and first SGW/PGW-A <NUM>. A handover may occur to a second access node B <NUM> in a second RAN-B <NUM> using a second MME-B <NUM> and a second SGW/PGW-A <NUM>.

As the UE <NUM> moves between the two RAN constellations <NUM> and <NUM> (either for handover or due to multi-connectivity), a new context is established in the second MME-B <NUM>. In the case of handover, after the handover is completed, the first MME-A <NUM> may remove its context associated with the UE <NUM>.

In the case of separate GWs <NUM> and <NUM>, e.g., due to SIPTO within an operator, or inter-operator multi-connectivity and offload, the UE establishes a new IP address at the target RAN constellation.

In the case of inter-operator multi-connectivity, the UE <NUM> may use separate subscriptions on each operator or it may be roaming.

<FIG> is a flow diagram illustrating one example of how a handover between access nodes on different RANs with MME relocation and separate SGW/PGWs may be implemented using dual active connections for a UE within the network environment of <FIG> according to some aspects/embodiments. The UE device <NUM> may have previously established service <NUM> with the first access node A <NUM>, first MME-A <NUM>, and PGW/SGW <NUM>. This may include establishing/obtaining a first connection with the serving first access node A <NUM> while using a first MME-A <NUM> and the SGW/PGW <NUM> and having a first UE context <NUM> at the AAA <NUM>. A dual active connection handover may be triggered <NUM> autonomously by a UE device decision, or the network may indicate (e.g., in an RRC message for the UE device <NUM>) to establish a new connection (e.g., in a CC Handover command with no context).

Upon occurrence of this triggering event <NUM>, the UE device <NUM> establishes a second connection with the second access node B <NUM> by sending a random access preamble <NUM> to the second access node B <NUM> and, in reply, receiving a random access response <NUM>. If UE device <NUM> does not need IP address continuity, the UE device <NUM> may establish a new PDN connection with the second access node B <NUM>. The UE device <NUM> may send a handover connection request <NUM> to the second MME-B <NUM>. The second access node B <NUM> also sends an initial UE message <NUM> (including the handover attachment request <NUM>) to the second MME-B <NUM> (e.g., the MME serving the second access node B <NUM>). Upon receipt of the initial UE message <NUM>, the second MME-B <NUM> sends an update location request <NUM> to the AAA <NUM> and receives an update location acknowledgement <NUM> from the AAA <NUM>, which includes subscription data for the UE device's second connection. The second MME-B <NUM> then sends a create session request <NUM> to the second PGW/SGW <NUM> and receives, in reply, a create session response <NUM>. The second MME-B <NUM> then sends an initial UE context setup message <NUM> to the second access node B <NUM>. The second access node B <NUM> sends a connection setup command <NUM> to the UE device <NUM>. In response, the UE device <NUM> sends a connection setup complete message <NUM> to the second access node B <NUM>. The second access node B <NUM> may then send an initial UE context setup response <NUM> to the second MME-B <NUM>.

The second MME-B <NUM> then sends a notify request <NUM> to the AAA <NUM> and receives a notify response <NUM>. At this point the AAA <NUM> updates the UE context <NUM> for the UE device <NUM> so that it includes the second MME-B and a GUTI2. Meanwhile, the first connection with the first access node A <NUM> remains active and operational up to this point. The network may release the first connection <NUM> from the first access node <NUM>, e.g., the UE device <NUM> may deactivate the PDN connections with first MME-A <NUM>, or the network may release the first connection due to lack of activity.

Note that, if the UE device <NUM> needs IP address continuity, the UE device <NUM> may perform the procedure illustrated in <FIG>.

<FIG> illustrates a functional block diagram of at least one embodiment of a user equipment (UE) device <NUM> with dual active connection capabilities. The UE device <NUM> may generally include a processing circuit <NUM> (e.g., processor, processing module, etc.) coupled to a memory device <NUM> (e.g., memory module, memory, etc.), one or more subscriber identity (ID) module(s) <NUM>, and/or and a wireless communication circuit <NUM> according to some aspects/embodiments.

The processing circuit <NUM> may be configured to establish a wireless connection via the wireless communication circuit <NUM> to send and/or receive information from a network (e.g., from an access node). The processing circuit <NUM> may be coupled to the memory circuit <NUM> such that the processing circuit <NUM> can read information from, and write information to, the memory device <NUM>. The processing circuit <NUM> may also include a network connection module/circuit <NUM> for establishing a network connection (via the wireless communication circuit <NUM>) with one or more access nodes. The processing circuit <NUM> may also include a device authentication module/circuit <NUM> for performing the various steps of authenticating the user equipment <NUM> with a network. The processing circuit <NUM> may also include a dual active handover module/circuit <NUM> for performing a handover from a first access node to a second access node while maintaining two simultaneous active connections during the handover process.

The UE device <NUM> may also include one or more subscriber (or user) identity module(s) <NUM> coupled to the processing circuit <NUM>. The subscriber identity module(s) <NUM> may comprise any subscriber identity module, such as a Subscriber Identification Module (SIM), a Universal Subscriber Identity Module (USIM), a CDMA Subscriber Identification Module (CSIM) or a Removable User Identification Modules (RUIM). The subscriber identity module may comprise cryptographic subscriber information contained therein, and adapted for use in subscriber authentication procedures.

The wireless communication circuit <NUM> may include one or more transmitters <NUM> and one or more receivers <NUM>. The one or more receiver(s) <NUM> may be configured to allow the user equipment device <NUM> to maintain two or more active connections with different access nodes during a handover from a first access node to a second access node.

According to one or more features, the processing circuit <NUM> may be configured to perform any or all of the processes, functions, steps and/or routines related to the various UE devices described <FIG> (e.g., UE device <NUM>, <NUM>, <NUM>, <NUM>). As used herein, the term "configured" in relation to the processing circuit <NUM> may refer to the processing circuit <NUM> being one or more of adapted, employed, implemented, or programmed to perform a particular process, function, step and/or routine according to various features described herein.

<FIG> is a flow diagram illustrating the claimed method operational in a UE device to facilitate a handover from a first access node to a second access node while maintaining dual active connections according to some aspects/embodiments. The UE device may establish a first connection with a first access node for communication services (e.g., data services) via a first network <NUM>. The UE device may then ascertain or receive an indication that a handover to a second access node is to occur <NUM>. The UE device may establish a second connection with a second access node for communication services (e.g., data services), via the first network or a second network, while the first connection remains established <NUM>. As part of this process, the UE device may perform authentication with an entity of the first network. During this handover, both the first connection and second connection are concurrently available, established, and/or active.

The UE device may receive packets over both the first connection and second connection during handover <NUM>. The UE device may reorder the packets received and delete duplicate packets received during handover <NUM>. For example, a packet identifier may be used to reorder and/or delete duplicates. During the handover and prior to terminating the first connection, the UE device may transmit packets over the second connection <NUM>.

The UE device may subsequently terminate the first connection once the handover is completed <NUM>. In one example, the user equipment device may ascertain or determine to terminate the first connection, e.g., once the second connection becomes fully active. In another example, the UE device may receive an indication from the first network to terminate the first connection. In some examples, determining when the handover is completed may be based on a message (or indication) received from the first or second access node. For instance, a handover completed indication may include an end marker (i.e., the last packet from the first node is sent with a flag indicating no more data). In another example, the handover completed indication may include a radio resource control (RRC) release from the first access node.

In one example, obtaining an indication that the handover should occur may include receiving a message from the first access node that the handover should occur. In another example, obtaining an indication that the handover should occur includes making an autonomous decision to initiate the handover.

In various examples, the first connection and second connection may be wireless connections over a single radio access network or over different radio access networks.

In one example, the first connection and second connection are established by sharing a single receiver at the user equipment device.

In another example, the first connection is established via a first receiver at the user equipment device and the second connection is established via a second receiver at the user equipment device.

When establishing the second connection, a new internet protocol (IP) address may be created for the user equipment device. Alternatively, when establishing the second connection, a previous internet protocol (IP) address used by the first connect for the user equipment device may be reused.

<FIG> illustrates a functional block diagram of at least one embodiment of an access node <NUM> that facilitates dual active handovers for user equipment devices. The access node <NUM> may generally include a processing circuit <NUM> (e.g., processor, processing module, etc.) coupled to a memory device <NUM> (e.g., memory module, memory, etc.), a network interface circuit <NUM>, and/or and a wireless communication circuit <NUM> according to some aspects/embodiments.

The processing circuit <NUM> may be configured to establish a wireless connection to one or more user equipment devices via the wireless communication circuit <NUM>. The access node <NUM> is configured to transmit packets between a wireless network and the network interface circuit <NUM> to/from a serving network. The processing circuit <NUM> may be coupled to the memory circuit <NUM> such that the processing circuit <NUM> can read information from, and write information to, the memory device <NUM>. The processing circuit <NUM> may also include a network connection module/circuit <NUM> for establishing a network connection (via the wireless communication circuit <NUM>) with one or more user equipment devices (UEs). The processing circuit <NUM> may also include a device authentication module/circuit <NUM> for performing the various steps of authenticating the user equipment devices with the serving network. The processing circuit <NUM> may also include a dual active handover module/circuit <NUM> for performing a handover of communication services for a user equipment device to another access node. For instance, if the access node <NUM> maintains a first connection with a first user equipment device and decides to handover communication services for the first user equipment device to another access node, it may do so while maintaining first connection active or established until a second connection with the other access node is fully established.

The wireless communication circuit <NUM> may include one or more transmitters <NUM> and one or more receivers <NUM>.

According to one or more features, the processing circuit <NUM> may be configured to perform any or all of the processes, functions, steps and/or routines related to the various access node described and/or illustrated in <FIG> (e.g., UE device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>). As used herein, the term "configured" in relation to the processing circuit <NUM> may refer to the processing circuit <NUM> being one or more of adapted, employed, implemented, or programmed to perform a particular process, function, step and/or routine according to various features described herein.

<FIG> illustrates a method operational at a first access node for handing-off wireless services of a user equipment (UE) device to another access node using dual active connections according to some aspects/embodiments. A first connection is established between the first access node and a UE device for communication services via a first network <NUM>. The first access node may receive/obtain information from the UE device related to a quality of the first connection <NUM>. The first access node may decide (or alternatively is instructed to) handover the communication services for the UE device to a second access node on a second network <NUM>. A handover request may then be sent by the first access node to initiate the handover <NUM>. For instance, the handover request may be sent to the second access node (as illustrated in <FIG>) or to another network node (as illustrated in <FIG>, MME <NUM>). The first access node may continue to receive packets intended for the UE device even after the handover has started <NUM>. The first access node may bicast (e.g., transmitted concurrently, simultaneously, or serially) the packets to both the UE device and the second access node during the handover <NUM>. In an alternative implementation, rather than bicasting the packets, the first access node may forward the packets to either the UE device or the second access node. The first connection may be terminated once the handover is completed <NUM>.

One or more of the components, steps, features and/or functions illustrated in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and/or <NUM> may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from the present disclosure.

Also, it is noted that at least some implementations have been described as a process that is depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the
order of the operations may be re-arranged. A process is terminated when its operations are completed. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or the main function.

Moreover, embodiments may be implemented by hardware, software, firmware, middleware, microcode, or any combination thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine-readable medium such as a storage medium or other storage(s). A processor may perform the necessary tasks. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc..

A processing circuit, as described herein (e.g., the processing circuit <NUM> and/or <NUM>), may comprise circuitry configured to implement desired programming provided by appropriate media in at least one embodiment. For example, a processing circuit may be implemented as one or more of a processor, a controller, a plurality of processors and/or other structure configured to execute executable instructions including, for example, software and/or firmware instructions, and/or hardware circuitry. Embodiments of a processing circuit may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic component, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor but, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing components, such as a combination of a DSP and a microprocessor, a number of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. These examples of the processing circuit are for illustration and other suitable configurations within the scope of the present disclosure are also contemplated.

As described herein above, memory circuit, such as memory device <NUM> may represent one or more devices for storing programming and/or data, such as processor executable code or instructions (e.g., software, firmware), electronic data, databases, or other digital information. A memory circuit may be any available media that can be accessed by a general purpose or special purpose processor. By way of example and not limitation, memory circuit may include read-only memory (e.g., read-only memory ROM, erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM)), random access memory (RAM), magnetic disk storage mediums, optical storage mediums, flash memory devices, and/or other non-transitory computer-readable mediums for storing information.

The terms "machine-readable medium", "computer-readable medium", and/or "processor-readable medium" may include, but are not limited to portable or fixed storage devices, optical storage devices, and various other non-transitory mediums capable of storing, containing or carrying instruction(s) and/or data. Thus, the various methods described herein may be partially or fully implemented by instructions and/or data that may be stored in a "machine-readable medium", "computer-readable medium", and/or "processor-readable medium" and executed by one or more processors, machines and/or devices.

The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executable by a processor, or in a combination of both, in the form of processing unit, programming instructions, or other directions, and may be contained in a single device or distributed across multiple devices. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of non-transitory storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium.

Those of skill in the art would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both.

The various features of the disclosure described herein can be implemented in different systems without departing from the disclosure. It should be noted that the foregoing embodiments are merely examples and are not to be construed as limiting the disclosure. The description of the embodiments is intended to be illustrative, and not to limit the scope of the disclosure. As such, the present teachings can be readily applied to other types of apparatuses and many alternatives, modifications, and variations will be apparent to those skilled in the art.

In the following further examples are described to facilitate the understanding of the invention.

In on further example, a method operational on a user equipment device for facilitating a dual active handover is described, the method comprising establishing a first connection with a first access node for communication services via a first network, obtaining an indication that a handover to a second access node is to occur, establishing a second connection with a second access node for communication services, via the first network or a second network, while the first connection remains established and terminating the first connection once the handover is completed. Obtaining an indication that the handover is to occur may include receiving a message or indicator from the first access node that the handover is to occur. Further, obtaining an indication that the handover is to occur may include making an autonomous decision by the user equipment device to initiate the handover. The first connection and second connection may be wireless connections over a single radio access network or over different radio access networks. The first connection and second connection may be concurrently active during the handover. The first connection and second connection may be established by sharing a single receiver at the user equipment device. Also, the first connection may be established via a first receiver at the user equipment device and the second connection may be established via a second receiver at the user equipment device. The method may further comprise receiving packets over both the first connection and second connection during handover. Also, the method may comprise reordering the packets received and deleting duplicate packets received during handover. Further, the method may comprise transmitting packets over the second connection during handover and prior to terminating the first connection. The method may also comprise creating a new internet protocol (IP) address for the user equipment device when establishing the second connection. Further, the method may comprise reusing a previous internet protocol (IP) address, used by the first connection, for the user equipment device for the second connection. The method may also comprise receiving a handover completed indication from the first access node or second access node. Further, the handover completed indication may include at least one of: an end marker indicating no more data to be transmitted and a radio resource control release from the first access node.

In yet another further example, a user equipment device is described, the user equipment device comprising: a wireless communication circuit configured to communicate with a first network and a processing circuit coupled to the wireless communication circuit and configured to: establish a first connection with a first access node for communication services via a first network, obtain an indication that a handover to a second access node is to occur, establish a second connection with a second access node for communication services, via the first network or a second network, while the first connection remains established and terminate the first connection once the handover is completed. The first connection and second connection may be wireless connections over a single radio access network or over different radio access networks. The first connection and second connection may be concurrently active during the handover. Te processing circuit may be further configured to: transmit packets over the second connection during the handover.

In yet another further example, a non-transitory machine-readable storage medium having one or more instructions stored thereon for facilitating a dual active handover is described, the instructions, which when executed by at least one processor, causes the at least one processor to: establish a first connection with a first access node for communication services via a first network, obtain an indication that a handover to a second access node is to occur, establish a second connection with a second access node for communication services, via the first network or a second network, while the first connection remains established and terminate the first connection once the handover is completed.

Claim 1:
A method operational on a user equipment device for facilitating a dual active handover, comprising:
establishing (<NUM>) a first connection over a first radio access network, RAN, with a first access node;
obtaining (<NUM>) an indication that a handover to a second access node is to occur;
making an autonomous decision to initiate the handover;
establishing (<NUM>) a second connection over a second RAN with the second access node while the first connection remains established, wherein the first RAN differs from the second RAN and wherein the first connection is established via a first receiver at the user equipment device and the second connection is established via a second receiver at the user equipment device; receiving (<NUM>) one or more bicast packets from the first access node and the second access node, during the handover, wherein the first connection and second connection are concurrently active during the handover;
transmitting (<NUM>) one or more packets over the second connection during handover; and
terminating (<NUM>) the first connection once the handover is completed.