System and method for paging in a communications system

A method for paging a user equipment (UE) includes receiving a generic page indication for the UE, the generic page indication including a list of radio access networks (RANs), selecting a subset of the list of RANs, sending a RAN-specific page indication for each RAN in the subset of the list of RANs, receiving a first RAN-specific page response associated with the UE, and sending a generic page response corresponding to the first RAN-specific page response.

TECHNICAL FIELD

The present disclosure relates generally to a system and method for digital communications, and, in particular embodiments, to a system and method for paging in a communications system.

BACKGROUND

Generally, in traditional cellular networks, the point where a mobile device attaches and where mobility is controlled is a mobility control node of the core network. As an example, in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) compliant network, the node is referred to as a mobility management entity (MME). Each mobility control node has control of the mobile devices within a particular domain, as well as the responsibility for locating the mobile devices and establishing connectivity when communications is needed, such as paging the mobile devices when data service with the mobile device is needed.

Because the mobility control nodes belong to a particular core network, they are intrinsically coupled to the radio access technology (RAT) or technologies (RATs) used in radio access networks (RANs) coupled to that core network. Traditionally, these coupling relationships between RANs and core network nodes have been RAT-specific, with a core network having only one RAT (or at most, a small number of closely related RATs) with which it can communicate. As an example, a MME is specific to mobile devices using 3GPP LTE access. Communicating with devices using other access technologies requires special purpose interworking procedures between the respective core networks, and in general, a particular mobile device would still be associated with one radio access technology or another. For example, a 3GPP LTE network may communicate with a CDMA2000 network to perform an inter-RAT handover, but after the handover, the 3GPP LTE MME considers that the mobile device is no longer under the coverage of the 3GPP LTE MME.

In future networks, using software defined network (SDN) architecture and/or virtualized network functions, the mobility control node will be replaced by a logical function, typically hosted in an Internet protocol (IP) cloud. The virtualized function has no special reason to communicate with only one RAT, and it is reasonable that a single mobility control function may manage devices using multiple RATs.

SUMMARY

Example embodiments provide a system and method for paging in a communications system.

In accordance with an example embodiment, a method for paging a user equipment (UE) is provided. The method includes receiving, by an adaptation function, a generic page indication for the UE, the generic page indication including a list of radio access networks (RANs), selecting, by the adaptation function, a subset of the list of RANs, sending, by the adaptation function, a RAN-specific page indication for each RAN in the subset of the list of RANs, receiving, by the adaptation function, a first RAN-specific page response associated with the UE, and sending, by the adaptation function, a generic page response corresponding to the first RAN-specific page response.

Optionally, in any of the preceding embodiments, wherein at least two RANs in the list of RANs operate using distinct radio access technologies (RATs).

Optionally, in any of the preceding embodiments, wherein the adaptation function receives a plurality of RAN-specific page responses including the first RAN-specific page response associated with the UE, and wherein the method further comprises selecting, by the adaptation function, the first RAN-specific page response from the plurality of RAN-specific page responses in accordance with a selection criteria.

Optionally, in any of the preceding embodiments, wherein the selection criteria includes at least one of a preferred RAN for a service being setup by the generic page indication, a preferred RAN for the UE, RAN capabilities, UE capabilities, RAN condition, or UE condition.

Optionally, in any of the preceding embodiments, wherein the generic page indication is associated with a service with a preferred RAN, and wherein the subset of the list of RANs is selected in accordance with the preferred RAN.

Optionally, in any of the preceding embodiments, wherein at least one of the RAN-specific page indications include information to direct the UE to the preferred RAN.

Optionally, in any of the preceding embodiments, wherein at least a first RAN-specific page indication of the RAN-specific page indications includes a data frame encapsulating a second RAN-specific page indication associated with the preferred RAN or RAN-specific information associated with the preferred RAN.

Optionally, in any of the preceding embodiments, wherein the adaptation function receives a plurality of RAN-specific page responses including the first RAN-specific page response associated with the UE, and wherein the method further comprises sending, by the adaptation function, to RAN devices associated with the plurality of RAN-specific page responses other than the first RAN-specific page response, RAN-specific messages indicating the RAN devices to release the UE.

In accordance with an example embodiment, a method for operating a UE is provided. The method includes receiving, by the UE, a first RAN-specific page indication from a first RAN device, the first RAN-specific page indication including information regarding a preferred RAN, sending, by the UE, a RAN-specific page response to a second RAN device, and participating, by the UE, in a RAN change in accordance with the first RAN-specific page indication.

Optionally, in any of the preceding embodiments, wherein the first RAN-specific page indication includes a redirection indicator, and wherein participating in the RAN change comprises redirecting to the preferred RAN.

Optionally, in any of the preceding embodiments, wherein the first RAN-specific page indication includes a handover indicator, and wherein participating in the RAN change comprises performing a handover to the preferred RAN.

Optionally, in any of the preceding embodiments, wherein the first RAN device and the second RAN device are one and the same.

Optionally, in any of the preceding embodiments, wherein the first RAN device and the second RAN device are different RAN devices, wherein the second RAN device serves the preferred RAN, and wherein the first RAN-specific page indication from the first RAN device encapsulates a second RAN-specific page indication associated with the preferred RAN or RAN-specific information associated with the preferred RAN.

Optionally, in any of the preceding embodiments, wherein the first RAN-specific page indication comprises a logical link control (LLC) Protocol Discrimination (LPD) based data frame with an EtherType field indicating that the LPD based data frame is an EtherType “89-0d” frame, wherein the second RAN-specific page indication or the RAN-specific information associated with the preferred RAN is encapsulated in a payload of the LPD based data frame, and wherein a payload type indicator of the LPD based data frame indicates a paging protocol of the preferred RAN, the method further comprising obtaining, by the UE, the payload type indicator and the payload of the LPD based data frame from the first RAN-specific page indication, and forwarding, by the UE, the payload to a UE protocol stack associated with the preferred RAN based on a value of the payload type indicator, wherein the UE protocol stack associated with the preferred RAN generates the RAN-specific page response.

In accordance with an example embodiment, a method for paging a UE is provided. The method includes receiving, by a first RAN device serving a first RAN, a first RAN-specific page indication for the UE, determining, by the first RAN device, that the UE is camped on a second RAN, sending, by the first RAN device, a second RAN-specific page indication to a second RAN device serving the second RAN, the second RAN-specific page indication including a RAN-specific paging message, and receiving, by the first RAN device, a first RAN-specific page response from the UE.

Optionally, in any of the preceding embodiments, wherein the RAN-specific paging message is encapsulated in the second RAN-specific page indication.

Optionally, in any of the preceding embodiments, wherein the second RAN-specific page indication comprises a data frame.

Optionally, in any of the preceding embodiments, further comprising forwarding, by the first RAN device, the first RAN-specific page response from the UE to an adaptation function, wherein the first RAN-specific page indication for the UE is received from the adaptation function.

In accordance with an example embodiment, a UE is provided. The UE includes one or more processors, and a computer readable storage medium storing programming for execution by the one or more processors. The programming including instructions to configure the UE to receive a first RAN-specific page indication from a first RAN device, the first RAN-specific page indication including information regarding a preferred RAN, send a RAN-specific page response to a second RAN device, and participate in a RAN change in accordance with the first RAN-specific page indication.

Optionally, in any of the preceding embodiments, wherein the first RAN-specific page indication includes a redirection indicator, and wherein the programming includes instructions to configure the UE to redirect to the preferred RAN.

Optionally, in any of the preceding embodiments, wherein the first RAN-specific page indication includes a handover indicator, and wherein the programming includes instructions to configure the UE to perform a handover to the preferred RAN.

Practice of the foregoing embodiments enables the paging of a mobile device when the mobility management function does not know where (e.g., in which one of a plurality of RATs) to locate the mobile device.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The embodiments will be described with respect to example embodiments in a specific context, namely networks that use a mobility control function to manage mobile devices using multiple radio access technologies (RATs). The embodiments may be applied to standards compliant communications systems and non-standards compliant communications systems that use a mobility control function to manage mobile devices using multiple RATs.

In a virtualized network, it makes sense to abstract the concept of device attachment, so that the service layer has no special dependency on a particular access network. As an example, a high-speed data service needs to know that the serving network can provide a requisite data rate to the mobile device, but there is no need to distinguish between the networks that provide the needed data rate using the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) or Institute of Electrical and Electronics Engineers (IEEE) 802.11 (commonly referred to as Wi-Fi or wireless local area network (WLAN)) or some other RAT. The abstraction may be referred to as a “network as a service” (NaaS) concept and is a major use case for the network function virtualization concept. The NaaS concept is seen as enabling a high level of future flexibility in integrating different RATs in order to provide a seamless user experience.

A mobile device may be attached to the mobility management function through any RAT, e.g., a first RAT. The mobile device may subsequently move to a different RAT, e.g., a second RAT, through an inter-RAT handover, for example. In addition, some devices may be able to attach through several RATs at the same time, with a particular service being delivered using whichever radio access network (RAN) that can best support the requirements (e.g., voice services using a cellular RAN and data services using a Wi-Fi RAN). In these environments, the mobility management function may not know which RAN is serving the mobile device at any particular moment, especially if the mobile device is camped in an idle mode on the RANs. In a situation where the battery life of a mobile device is a major concern, a significant advantage may be to minimize signaling between the mobile device and the network infrastructure when the mobile device is in an idle mode, even as the mobile device moves between regions where the different regions may have preferred coverage from different RANs (e.g., due to variations in radio environments). Minimizing signaling would allow the mobile device to benefit from moving freely between RANs without any explicit signaling to update the mobility management function. Therefore, when there is a need to make contact with the mobile device in the idle mode (e.g., paging for a mobile device terminated service), it cannot always be assumed that the mobility management function knows where (e.g., via which RAN) to locate the mobile device.

FIG. 1illustrates an example communications system100. Communications system100includes a first RAN (RAN_A)105and a second RAN (RAN_B)107. Communications system100also includes a user equipment (UE)110that is camped in RAN_B107, and is in an idle mode, which means that UE110is not actively participating in communications. The two RANs are connected to an adaptation function115that abstracts RAN functions into a form similar to an application programming interface (API) for a software defined network (SDN). Adaptation function115may not be necessary within 3GPP compliant RATs but provides flexibility with other RATs. Adaptation function115may be implemented in an entity in the core network. Alternatively, adaptation function115may be implemented in a stand-alone device, as a distributed function in multiple network devices, and so on. Adaptation function115is informed regarding paging message formats used in the different RATs, for example.

The API is provided to routers120and122that interface with a SDN125. In SDN125, there are virtualized mobility functions (VMM)130and virtualized gateway functions (VGW)135. VMM130controls devices attached through RAN_A105and RAN_B107, while VGW135provides connectivity to external networks. It should be appreciated that VMM130and VGW135may be instantiated on a single hardware entity, on separate hardware entities, in a centralized or distributed fashion, etc., depending on the architecture of SDN125.

While it is understood that communications systems may employ multiple routers, RANs, and UEs, in various network topologies, only two routers, two RANs, and one UE are illustrated for simplicity.

SDN125communicates with RAN_A105and RAN_B107. As an example, RAN_A105may be 3GPP LTE compliant while RAN_B107is a fifth generation (5G) compliant RAT. Communications with non-3GPP and pre-fourth generation (pre-4G) RATs are also possible.

UE110has one registration that covers both RANs and the registration is not updated each time UE110switches RANs. In state of the art communications systems, when a UE is registered with the core network, and in idle mode “somewhere” (i.e., camped in the coverage of one of the RANs (RAN_A105or RAN_B107)), VMM130does not know which RAN the UE is camped in. This uncertainty leads to the question, how does SDN125page UE110to set up a service?

FIG. 2illustrates an example communications system200, highlighting the processing of data intended for a UE210arriving at an SDN225. In general, when data arrives at SDN225for UE210, a route is needed by a VGW235to deliver the data to UE210. A VMM230has a context for UE210but no active route to UE210. VMM230is responsible for paging UE210to establish a radio resource control (RRC) connection with UE210to provide the route to VGW235. However, VMM230does not know if UE210is camped on RAN_A205or RAN_B207, therefore, VMM230does not know if it should page RAN_A205or RAN_B207. A potentially easy solution would be to page both RAN_A205and RAN_B207, which is commonly referred to as flood paging.

FIG. 3illustrates an example communications system300, highlighting the paging procedure. Communications system300includes a RAN_A305and a RAN_B307with a UE310camped in RAN_B307but in an idle mode. The two RANs are connected to an adaptation function315, which is connected to an SDN325. In SDN325, there is a VMM330and a VGW335.

At event320, data arrives at SDN325for delivery to UE310. VGW335determines that a route is needed to get the data to UE310, as well as identifies a VMM (e.g., VMM330) to which UE310is attached. VGW335sends a route request340to VMM330. VMM330determines one or more RANs on which UE310may be camped. In the scenario illustrated inFIG. 3, historical information (e.g., serving RAT information at the time UE310became attached to VMM330) may indicate that UE310has been served by RAN_A305and RAN_B307. Alternatively, UE310may have been configured, while served by one of RAN_A305and RAN_B307, to move freely between RAN_A305and RAN_B307without needing to update its attachment status with the network. In either case, VMM330does not know on which RAN UE310is currently camped.

VMM330sends a page indication345to adaptation function315. Page indication345may be in a generic format, meaning that page indication345is not formatted for any particular RAN. In an embodiment, adaptation function315accepts generic page indications and generates page indications in RAN specific formats. Adaptation function315also translates page responses in a RAN specific format into a generic page response. Adaptation function315generates two page indications (one for each of the two RANs) with a first page indication350in a format compatible with RAN_A305and a second page indication352in a format compatible with RAN_B307. RAN_A305and RAN_B307transmit pages but only the page from RAN_B307is successful (meaning that a corresponding page response is received from UE310) because UE310is currently camped in RAN_B307. RAN_B307sends a page response355to adaptation function315in a format compatible with RAN_B307. Adaptation function315converts page response355into a page response360that is in a generic format and sends page response360to VMM330. VMM330generates routing information365in accordance with information in page response360and sends routing information365to VGW335.

According to an example embodiment, in a situation where a page indication for a UE that may be camped in a plurality of RANs is received, pages are sent in each RAN in the plurality of RANs. The paging of the UE in multiple RANs is commonly referred to as flood paging.

According to an example embodiment, in a situation where a page indication for a UE that may be camped in a plurality of RANs is received, a subset of the plurality of RANs is selected and a page is sent to the UE using each RAN in the subset of the plurality of RANs. The page sent in a particular RAN is in a format compatible with the RAN.

FIG. 4illustrates a diagram400highlighting messages exchanged and processing performed by devices participating in flood paging. Diagram400highlights messages exchanged and processing performed by a VMM405, an adaptation function407, a RAN_A device409, a RAN_B device411, and a UE413. Adaptation function407may be implemented in an entity in the core network. Alternatively, adaptation function407may be implemented in a stand-alone device, as a distributed function in multiple network devices, and so on.

VMM405sends a page indication to adaptation function407(event420). Page indication is in a generic format and may include a RAN list. The RAN list comprises a list of RANs that have served UE413in the past, or for which the attachment status of UE413in VMM405is otherwise valid. In general, the attachment status of a UE at a VMM comprises a list of RANs that may have served or may potentially serve the UE. The RAN list may be age limited, meaning that older RANs, i.e., RANs for which the UE's attachment status is less current, may not be listed. Adaptation function407generates page indications for each RAN in the RAN list, which in the scenario illustrated inFIG. 4, includes 2 RANs, RAN_A (which may be a 3GPP LTE compliant RAN) and RAN_B (which may be a 5G compliant RAN). The page indication for each RAN follows the format associated with the RAN. Adaptation function407sends the two page indications to the respective RANs (events422and424).

RAN_A device409, e.g., a 3GPP evolved NodeB (eNB), sends a radio resource control (RRC) page message (event426) in accordance with the standard paging behavior of an eNB when the core network indicates a page. However, because UE413is not camped in RAN_A, there is no reply (circle428). RAN_B device411, e.g., a 5G device such as a next generation (NG) Node B (gNB), sends a 5G page message (event430) in accordance with the paging (or equivalent functionality) procedures of the 5G RAN. UE413receives the 5G page and sends a 5G page response (event432). RAN_B device411sends the 5G page response to adaptation function407(event434). RAN_A device409may send a page failure to adaptation function407if RAN_A supports page failure messages (event436). It is noted that 3GPP LTE does not support page failure messages. A page failure message may be useful to indicate to adaptation function407that a page indication failed to receive a response. In situations where a RAN does not support page failure messages (such as in 3GPP LTE compliant RANs), a time-out mechanism may be used to determine if the page indication did not receive a response, and to either retry the paging procedure or give up.

Adaptation function407converts the 5G page response into a generic page response and sends the generic page response to VMM405(event438). Additional signaling is performed to establish service for UE413(block440).

It is noted with flood paging that:Although a response was received from a RAN, the RAN that responded may not provide the best access for the particular service being setup. This leads to suboptimal network capabilities, as an example, Wi-Fi may be used to setup a voice service. Alternatively, the RAN that responded may be more heavily loaded, leading to greater difficulty in meeting quality of service (QoS) requirements. Furthermore, there may be a preference (e.g., user) for a particular RAN to provide access for the particular service; andMore than one page response may be received. As an example, the UE may be a dual radio device, a dual SIM dual standby (DSDS) device, and so on. Therefore, in the worst case, the UE can respond to multiple page indications simultaneously. The RANs may or may not be informed about the simultaneous camping by the UE.

As an illustrative example, suppose that a service being setup prefers a first RAN (e.g., 3GPP LTE) over a second RAN (e.g., 5G). Furthermore, suppose that the VMM knows that the UE can use the first RAN, and that the UE's attachment to the core network would allow it to use the first RAN, but the VMM does not necessarily know on which RAN the UE is currently camped. Hence, it is desired that the UE be paged wherever the UE is camped, but it is also desired to move the UE into the first RAN to provide the service being setup, because the first RAN is the preferred RAN in this illustrative example. In this situation, there is a possibility that the UE is camped on the second RAN and receives paging on the second RAN, establishing a need to move the UE into service on the first RAN. In 3GPP LTE, a similar situation occurs in paging for circuit switched fallback (CSFB), where a goal is for the UE to end up on a circuit switched supporting RAT. As an example, redirection or handover may be used to move the UE into the first RAN. A similar effect could be achieved by so-called “cross-paging”, where a page in a first RAN is used to page the UE with a direction to move immediately to a second RAN and to respond on the second RAN. However, cross-paging is not supported in 3GPP LTE today.

FIG. 5illustrates a diagram500highlighting messages exchanged and processing performed by devices participating in access selection using redirection. Diagram500highlights messages exchanged and processing performed by a VMM505, an adaptation function507, a RAN_A device509(e.g., an LTE eNB), a RAN_B device511(e.g., a 5G gNB), and a UE513. Adaptation function507may be implemented in an entity in the core network. Alternatively, adaptation function507may be implemented in a stand-alone device, as a distributed function in multiple network devices, and so on.

VMM505sends a page indication to adaptation function507(event520). Different page indications may be sent for different RANs, based on a preferred RAN for a service being setup. As an illustrative example, if RAN_A is the preferred RAN, then a normal page indication is sent for RAN_A and a redirect to RAN_A page indication is sent for RAN_B. Adaptation function507generates RAN specific page indications for the RANs. As an example, adaptation function507generates a 3GPP LTE SiAP paging message for RAN_A and a 5G paging message with redirection information for RAN_B. Adaptation function507sends the page indications to respective RANs (events522and524).

RAN_A device509sends an RRC paging message (event526) but UE513is not camped in RAN_A so there is no reply (circle528). RAN_B device511sends a 5G page message (event530). Because UE513is camped in RAN_B, UE513sends a 5G page response (event532). UE513and RAN_B device511participate in a redirection to RAN_A (event534). UE513participates in a random access channel (RACH) procedure and sets up a connection on RAN_A (event536). RAN_A device509sends a page response, e.g., S1signaling, to adaptation function507(event538). Adaptation function507converts the page response in RAN_A format into a generic page response and sends the generic page response to VMM505(event540). The devices continue with service setup and commence communications in RAN_A (block542).

FIG. 6illustrates a diagram600highlighting messages exchanged and processing performed by devices participating in access selection using handover. Diagram600highlights messages exchanged and processing performed by a VMM605, an adaptation function607, a RAN_A device609(e.g., an LTE eNB), a RAN_B device611(e.g., a 5G gNB), and a UE613. Adaptation function607may be implemented in an entity in the core network. Alternatively, adaptation function607may be implemented in a stand-alone device, as a distributed function in multiple network devices, and so on.

VMM605sends a page indication to adaptation function607(event620). Different page indications may be sent for different RANs, based on a preferred RAN for a service being setup. As an illustrative example, if RAN_A is the preferred RAN, then a normal page indication is sent for RAN_A and a redirect to RAN_A page indication is sent for RAN_B. Adaptation function607generates RAN specific page indications for the RANs. As an example, adaptation function607generates a 3GPP LTE SiAP paging message for RAN_A and a 5G paging message with redirection information for RAN_B. Adaptation function607sends the paging messages to respective RANs (events622and624).

RAN_A device609sends an RRC paging message (event626) but UE613is not camped in RAN_A so there is no reply (circle628). RAN_B device611sends a 5G page message (event630). Because UE613is camped in RAN_B, UE613sends a 5G page response (event632). UE613and a plurality of network entities, including, e.g., adaptation function607that is serving as a proxy for core network entities, exchange signaling to perform bearer and connection setup (shown as a single event634to simplifyFIG. 6). In a first option, adaptation function607sends a page response indication from UE613camped in RAN_B to VMM605to complete the paging of UE613(event636).

In either option shown inFIG. 6, core network signaling associated with events634or642are forwarded to VMM605. The core network signaling forwarded to VMM605may be modelled as a response or paging response to complete the paging transaction. It is noted that 3GPP LTE supports the triggering of the handover in this scenario, e.g., using information element (IE) HandoverRestrictionList at an initial context setup, it is expected that 5G should as well.

In a situation wherein the UE is camped on both RAN_A and RAN_B at the same time and pages arrive on both RANs, a problem may arise if the UE responds to both pages. It may be possible that the UE is sufficiently knowledgeable and responds to only one of the two pages. Potentially, the UE may base a decision regarding which page to respond to according to a format of the pages, an order of arrival of the pages, a preference between RATs for the underlying service, etc. The multi-page problem may be a significant issue because the VMM may not know if the UE is capable of dual camping. One possible solution may be to use flood paging and if multiple page responses are received, the VMM can process the page responses individually, discard duplicates, and determine which page responses should result in a service establishment. This solution can result in lower latency at the cost of higher complexity in the VMM. Another possible solution may be to sequentially page the RANs, one at a time. The paging may be in order of preferred RANs, for example. As another example, the paging may also be in order of probability of UE location. As an illustrative example, the first page may be sent on a RAN with the highest probability that the UE is currently located, e.g., the RAN that has the most recent messages from the UE. The sequential paging solution may have higher latency but it is simpler to implement, e.g., the VMM can stop once a page response is received. The paging may be with or without redirection, depending upon the capabilities of the RANs and the UE.

FIG. 7illustrates a diagram700highlighting messages exchanged and processing performed by devices participating in access selection with the capability to resolve multiple page responses. Diagram700highlights messages exchanged and processing performed by a VMM705, an adaptation function707, a RAN_A device709, a RAN_B device711, and a UE713. Adaptation function707may be implemented in an entity in the core network. Alternatively, adaptation function707may be implemented in a stand-alone device, as a distributed function in multiple network devices, and so on.

VMM705sends a page indication to adaptation function707(event720). Adaptation function707sends a page in a RAN_A format to RAN_A device709(event722) and a page in a RAN_B format to RAN_B device711(event724). RAN_A device709sends a page message to UE713(event726) and UE713sends a page response to RAN_A device709(event728). RAN_A device709forwards the RAN_A page response to adaptation function707(event730), which sends a page response for RAN_A to VMM705(event732). RAN_B device711sends a page message to UE713(event734) and UE713sends a page response to RAN_B device711(event736). RAN_B device711forwards the RAN_B page response to adaptation function707(event738). The devices participate in establishing a service on RAN_A (block740). Adaptation function707sends a page response for RAN_B to VMM705(event742). It should be appreciated that event740may occur substantially asynchronously with respect to activity on RAN_B, e.g., with respect to events734,736,738, and742. For example, establishing service on RAN_A may begin before the reception of a page response on RAN_B.

In general, if a page results in multiple responses, multiple instances of the service should not be established. Therefore, because the service on RAN_A has already been established, VMM705sends a release indication for RAN_B to adaptation function707(event744). Adaptation function707sends a connection release for RAN_B to RAN_B device711(event746), which sends a connection release to UE713(event748) if UE713is still connected in RAN_B. If RAN_B is a cellular based RAN, the connection release in event748may comprise the release of an RRC connection of the UE with RAN_B. If RAN_B is a Wi-Fi based RAN, the connection release in event748may comprise the RAN_B device sending IEEE 802.11 management frame(s) to de-authenticate or dis-associate UE713, or to put UE713in a power save mode while maintaining the association with UE713. Examples of such IEEE 802.11 management frames may include the IEEE 802.11 defined Deauthentication frame, Disassociation frame, Wireless Network Management (WNM) Sleep Mode Response frame, etc.

In some situations, one or more of the plurality of RANs is not 3GPP LTE or 5G or any other similarly capable RAN. As an example, one or more of the plurality of RANs is Wi-Fi or 3G. As long as paging is supported in the particular RAN, the UE can be paged through the RAN. It is noted that Wi-Fi does not support paging per se. However, Wi-Fi supports the use of a beacon frame to establish contact and start exchanging data with a UE that is operating in a power save mode, resulting in functionality similar to paging in cellular networks. Similarly, 3G cellular systems support paging, while millimeter wave (mmWave) systems may be a different variant of 5G potentially including a differently defined paging procedure. The basic procedures described earlier are operable with such RANs, with adaptations as needed.

According to an example embodiment, in a situation where a page for a UE that may be camped in a plurality of RANs is received, and when at least one of the RANs is not 3GPP LTE or 5G or any other similarly capable RAN, pages are sent in each RAN in the plurality of RANs. If the RAN(s) that are not 3GPP LTE or 5G or any other similarly capable RANs, and do not support paging, techniques that are functionally similar to paging are used. As an illustrative example, if one of the RANs is Wi-Fi, then beacon frames are used in place of pages to contact UEs that are operating in a power save mode.

FIG. 8illustrates a diagram800highlighting messages exchanged and processing performed by devices participating in access selection with 5G and Wi-Fi RANs. Diagram800highlights messages exchanged and processing performed by a VMM805, an adaptation function807, a RAN_A device809(e.g., a 5G gNB), a RAN_B device811(e.g., a Wi-Fi AP), and a UE813. Adaptation function807may be implemented in an entity in the core network. Alternatively, adaptation function807may be implemented in a stand-alone device, as a distributed function in multiple network devices, and so on.

VMM805sends a page indication to adaptation function807(event820). Adaptation function807generates and sends a page in a RAN_A format to RAN_A device809(event822). However, RAN_B (the Wi-Fi RAN) does not support paging. Instead, beacon frames are used to contact UEs that are operating in a power save mode when downlink data is present for the UE. Adaptation function807sends an Ethernet frame including a downlink data packet to RAN_B device811(event824). The downlink data packet may be the packet data that triggered the page in event820. Alternatively, the downlink data packet may be a protocol data unit generated by adaptation function807serving the function of paging. RAN_B device811may convert the Ethernet frame into a RAN_B format frame, e.g., an IEEE 802.11 data frame.

RAN_A device809sends a page message to UE813(event826) and no reply is received because UE813is camped in RAN_B (event828). Page message sent by RAN_A device809may contain redirection information towards RAN_B. Otherwise, if UE813responds to the 5G page, UE813will have to subsequently handover to RAN_B.

The arrival of the converted data frame at a transmission queue of RAN_B device811triggers RAN_B device811to send a beacon frame with a traffic indication map (TIM) set to indicate that there is a downlink data frame buffered at RAN_B device811for UE813(event830). UE813sends back a power save poll (PS-Poll) frame to indicate that UE813is ready to receive the downlink data (event832). RAN_B device811sends the downlink data frame to UE813(event834) and UE813sends uplink data frame to RAN_B device811(event836). The uplink data frame may include an uplink data packet that UE813generates in response to the downlink data packet. For example, if the downlink data packet contains a Transmission Control Protocol (TCP) data segment, the uplink data packet may contain a TCP acknowledgement (ACK) segment. As another example, if the downlink data packet contains a protocol data unit generated by adaptation function807serving the function of paging, the uplink data packet may contain another protocol data unit generated by UE813serving the function of paging acknowledgement. Therefore, the uplink data packet may be used as an indication of the page response of UE813. RAN_B device811extracts the uplink data packet from the uplink data frame and sends an Ethernet frame including the uplink data packet to adaptation function807(event838). Adaptation function807sends a page response for RAN_B to VMM805(event840). As long as adaptation function807is able to recognize the uplink data from UE813as a page response, adaptation function807will be able to generate the page response for RAN_B and forward the page response to VMM805. The devices participate in service setup (block842).

FIG. 9illustrates a diagram900highlighting messages exchanged and processing performed by devices participating in access selection with 5G and Wi-Fi RANs, where 5G is the preferred RAN. Diagram900highlights messages exchanged and processing performed by a VMM905, an adaptation function907, a RAN_A device909(e.g., a 5G gNB), a RAN_B device911(e.g., a Wi-Fi access point (AP)), and a UE913. Adaptation function907may be implemented in an entity in the core network. Alternatively, adaptation function907may be implemented in a stand-alone device, as a distributed function in multiple network devices, and so on.

VMM905sends a page indication to adaptation function907(event920). Adaptation function907generates and sends a page in a RAN_A format to RAN_A device909(event922). Adaptation function907generates and sends a downlink Ethernet data frame targeted for UE913and encapsulating a 5G page (or alternatively, 5G paging information) to RAN_B device911(event924). RAN_B device911may convert the downlink Ethernet data frame into a RAN_B format frame, e.g., an IEEE 802.11 data frame. If the downlink data frame includes frequency information for RAN_A, the frequency information may be used to redirect UE913to RAN_A. UE913can transmit a page response over the air to RAN_A device909, as shown below. If the frequency information is not available or if the redirection feature is not available, the page response from UE913can occur over RAN_B followed with a handover to RAN_A.

RAN_A device909sends a page message to UE913(event926) and no reply is received because UE913is camped in RAN_B (circle928). The arrival of the converted data frame at a transmission queue of RAN_B device911triggers RAN_B device911to send a beacon frame with a TIM set to indicate that there is a downlink data frame buffered at RAN_B device911for UE913(event930). UE913sends back a PS-Poll frame to indicate that UE913is ready to receive the downlink data frame (event932). RAN_B device911sends the downlink data frame to UE913(event934). Because the downlink data frame includes the 5G page, UE913sends a 5G page response on RAN_A to RAN_A device909(event936). RAN_A device909sends the 5G page response to adaptation function907(event938). Adaptation function907sends a page response for RAN_A to VMM905(event940). The devices participate in service setup (block942).

As an illustrative example of the operations shown inFIG. 9, an adaptation function (or a RAN_A (e.g., 5G) device) sends an Ethernet frame to a RAN_B (e.g., Wi-Fi) device with an EtherType field containing value “89-0d” (expressed in hexadecimal), a Payload Type field containing a defined value to represent 5G paging (e.g., a value of “5”), a Payload field (such as payload field1005inFIG. 10A) containing a 5G paging message, and the Destination MAC field (such as destination MAC field1010inFIG. 10A) set to the MAC address of the UE.FIG. 10Aillustrates an example Ethernet frame1000.

The RAN_B device recognizes the value in the Destination MAC as belonging to a station associated with the RAN_B device, the RAN_B device converts the Ethernet frame to a logical link control (LLC) Protocol Discrimination based data frame (which is needed for transmission over Wi-Fi) before sending the information to the UE.FIG. 10Billustrates an example LLC Protocol Discrimination based data frame1020. The LLC field is defined in ISO/IEC 8802-2:1998. The subnetwork access protocol (SNAP) field is defined in IEEE 802.2014. The format of the SNAP header is according to IETF RFC1042. The EtherType value within the SNAP header may be copied from the EtherType field of the Ethernet frame received from the adaptation function. The Payload Type (such as Payload Type field1025) and Payload fields (such as Payload field1030) may be copied from the Payload field (e.g., Payload field1005) of the Ethernet frame.

Based on EtherType “89-0d” in the SNAP header, the data port in the UE routes the data frame to the station management entity (SME), which further processes the Payload Type field (e.g., Payload Type field1025).FIG. 10Cillustrates a table1040of example Payload Type values. The Payload Type is used by the UE to select a corresponding protocol handler for processing the Payload field (e.g., Payload field1030). For the Payload Type value representing 5G paging, the SME forwards the content of the Payload field (e.g., Payload field1030) to the 5G paging protocol hander for further processing.

FIG. 11illustrates a diagram1100highlighting messages exchanged and processing performed by devices participating in access selection with 5G and Wi-Fi RANs, where a 5G page is routed through Wi-Fi. Diagram1100highlights messages exchanged and processing performed by an adaptation function1105, a 5G RAN device1107, a Wi-Fi access point1109, and a UE1111with two protocol stacks (a Wi-Fi station protocol stack1113and a 5G UE protocol stack1115).

Adaptation function1105sends a 5G page to 5G RAN device1107(event1120). 5G RAN device1107determines that UE1111may be served by Wi-Fi AP1109(block1122). 5G RAN device1107generates and sends an Ethernet frame encapsulating the 5G page to Wi-Fi AP1109(event1124). Wi-Fi AP1109converts the format of the Ethernet frame into a LLC Protocol Discrimination based data frame, such as LLC Protocol Discrimination based data frame1020ofFIG. 10B(block1126). Wi-Fi AP1109sends the LLC Protocol Discrimination based data frame over the Wi-Fi air interface to UE1111(event1128). Wi-Fi station protocol stack1113processes the LLC Protocol Discrimination based data frame and recognizes the EtherType “89-0d” frame and the encapsulated 5G page included therein (block1130). Wi-Fi station protocol stack1113sends the 5G page to 5G UE protocol stack1115(event1132). 5G UE protocol stack1115sends a page response over the 5G air interface to 5G RAN device1107(event1134). 5G RAN device1107sends a page response for the 5G RAN to adaptation function1105(event1136).

The procedure illustrated inFIG. 11assumes that 5G paging supports some form of page with redirection. In other words, the paging message includes information about a target frequency and/or RAN. At a minimum, the paging message should include information to provide the UE sufficient information about the carrier that the UE will redirect to, in this case a 5G carrier. This is somewhat similar to frequency redirection in an Extended Channel Assignment Message in CDMA2000, wherein a target carrier frequency is included. The Wi-Fi protocol stack routes the message to the 5G protocol stack, which would then treat the message as if it had received the message on the 5G air interface. A more feature-rich version may allow the page record to indicate redirection to other systems, e.g., a page on the 5G RAN with redirection to Wi-Fi, LTE, etc.

According to an example embodiment, the Ethernet frame format for encapsulating the 5G page may be generated by a RAN_A (e.g., 5G) device, such as a 5G base station, instead of an adaptation function. If the encapsulating is performed by the RAN_A device, the Wi-Fi AP is not exposed to the adaptation function and/or core network. However, the RAN_A device would need to know the identifiers of the UEs served by the RAN_B (e.g., Wi-Fi) AP, as well as how to translate the identifiers to a destination MAC address for RAN_B.

It is noted that not all RANs, e.g., Wi-Fi, can truly support redirection. If a UE responds on Wi-Fi for a service that prefers 5G, the UE may be stuck using Wi-Fi for the service. This is due to the fact that there is currently no mechanism for a 3GPP core network to force a handoff from Wi-Fi to LTE. The Wi-Fi offload rules may not be sufficiently dynamic. Therefore, a service that has a strong preference for a particular RAN will not likely work well when the UE is paged into service on Wi-Fi.

Paging is only one procedure. In order to get to the paging procedure, the UE had to attach to the core network through Wi-Fi or some other RAN. A “radio as a service” (RaaS) scheme like this may work for systems that meet the requirements of the service. In principle that the example embodiments presented herein may work with non-3GPP RATs, but the interworking requirements may need to be developed in parallel with the SDN interfaces. The technique presented to deliver 5G paging over Wi-Fi as a management frame or a data frame with an encapsulation illustrates such an approach.

FIG. 12illustrates a flow diagram of example operations1200occurring in an adaptation function participating in flood paging. Operations1200may be indicative of operations occurring in an adaptation function as the adaptation function participates in flood paging.

Operations1200begin with the adaptation function receiving a generic page indication for a UE (block1205). The generic page indication may be received from a VMM. The generic page indication may include a list of RANs associated with the UE. The adaptation function selects a subset of the list of RANs (block1210). In an example embodiment, the subset comprises all RANs in the list of RANs. In another example embodiment, the subset comprises a single RAN in the list of RANs. In yet another example embodiment, the subset comprises two or more RANs in the list of RANs. The adaptation function generates and sends a RAN-specific page indication to each RAN in the subset of RANs (block1215). The RAN-specific page indications may include information about a preferred RAN for a service being setup by the page. The adaptation function receives at least one RAN-specific page response associated with a page response from the UE (block1220). Alternatively, the at least one RAN-specific page responses may be received from the preferred RAN as indicated in the RAN-specific page indications. The at least one RAN-specific page responses may be received from one or more of the RANs in the subset of RANs. The adaptation function generates and sends a generic page response to the VMM (block1225). The generic page response corresponds to and indicates the at least one RAN-specific page response associated with the page response from the UE. If the adaptation function receives more than one RAN-specific page response, the adaptation function may select one RAN-specific page response to generate the generic page response. The selection of the one RAN-specific page response may be based upon one or more selection criteria, such as a preferred RAN for a service being setup, a preferred RAN for the UE, RAN capabilities, UE capabilities, RAN condition, UE condition, and so on.

FIG. 13illustrates a flow diagram of example operations1300occurring in a UE participating in flood paging. Operations1300may be indicative of operations occurring in a UE as the UE participates in flood paging.

Operations1300begin with the UE receiving a RAN-specific page indication (block1305). The RAN-specific page indication may be received from a RAN device operating in the RAN associated with the RAN-specific page indication. The RAN-specific page indication may include information regarding a preferred RAN for a service being setup by the page. The UE sends a RAN-specific page response (block1310). The RAN-specific page response may be sent to the same RAN device that sent the RAN-specific page indication. The UE participates in a RAN change (block1315). The UE may participate in a redirection to change from a current RAN to the preferred RAN. Alternatively, the UE may participate in a handover to change from the current RAN to the preferred RAN.

FIG. 14illustrates a flow diagram of example operations1400occurring in a first RAN device participating in paging by routing a page through an alternate RAN. Operations1400may be indicative of operations occurring in a first RAN device as the first RAN device participates in paging a UE by routing a page through an alternate RAN.

Operations1400begin with the first RAN device receiving a first RAN-specific page indication for the UE (block1405). The first RAN device determines that the UE may be camped in a second RAN (block1410). The first RAN device generates and sends a second RAN-specific page indication (block1415). The second RAN-specific page indication includes the first RAN-specific indication or information included therein. As an example, the second RAN-specific page indication includes an encapsulated first RAN-specific page indication. As another example, the second RAN-specific page indication includes the information included in the first RAN-specific page indication in encapsulated form. The second RAN-specific page indication is sent to a second RAN device by the first RAN device. The second RAN-specific page indication may trigger the second RAN device to send a paging message to the UE on the second RAN. The first RAN device receives a first RAN-specific page response from the UE (block1420). The first RAN-specific page response is received over the first RAN.

FIG. 15illustrates a flow diagram of example operations1500occurring in a UE participating in paging by routing a page through an alternate RAN. Operations1500may be indicative of operations occurring in a UE as the UE participates in paging by routing a page through an alternate RAN.

Operations1500begin with the UE receiving a second RAN-specific page indication (block1505). The second RAN-specific page indication is received from a second RAN device. The second RAN-specific page indication includes a first RAN-specific page indication or information included in the first RAN-specific page indication, the first RAN-specific page indication or the information is in encapsulated form, for example. The UE forwards the first RAN-specific page indication or the information to a first RAN protocol stack in the UE (block1510). The first RAN-specific page indication or the information is forwarded from a second RAN protocol stack of the UE to the first RAN protocol stack in the UE. The UE sends a first RAN-specific page response (block1515). The first RAN-specific page response is sent over the first RAN to a first RAN device.

FIG. 16illustrates a block diagram of an embodiment processing system1600for performing methods described herein, which may be installed in a host device. As shown, the processing system1600includes a processor1604, a memory1606, and interfaces1610-1614, which may (or may not) be arranged as shown inFIG. 16. The processor1604may be any component or collection of components adapted to perform computations and/or other processing related tasks, and the memory1606may be any component or collection of components adapted to store programming and/or instructions for execution by the processor1604. In an embodiment, the memory1606includes a non-transitory computer readable medium. The interfaces1610,1612,1614may be any component or collection of components that allow the processing system1600to communicate with other devices/components and/or a user. For example, one or more of the interfaces1610,1612,1614may be adapted to communicate data, control, or management messages from the processor1604to applications installed on the host device and/or a remote device. As another example, one or more of the interfaces1610,1612,1614may be adapted to allow a user or user device (e.g., personal computer (PC), etc.) to interact/communicate with the processing system1600. The processing system1600may include additional components not depicted inFIG. 16, such as long term storage (e.g., non-volatile memory, etc.).

In some embodiments, one or more of the interfaces1610,1612,1614connects the processing system1600to a transceiver adapted to transmit and receive signaling over the telecommunications network.FIG. 17illustrates a block diagram of a transceiver1700adapted to transmit and receive signaling over a telecommunications network. The transceiver1700may be installed in a host device. As shown, the transceiver1700comprises a network-side interface1702, a coupler1704, a transmitter1706, a receiver1708, a signal processor1710, and a device-side interface1712. The network-side interface1702may include any component or collection of components adapted to transmit or receive signaling over a wireless or wireline telecommunications network. The coupler1704may include any component or collection of components adapted to facilitate bi-directional communication over the network-side interface1702. The transmitter1706may include any component or collection of components (e.g., up-converter, power amplifier, etc.) adapted to convert a baseband signal into a modulated carrier signal suitable for transmission over the network-side interface1702. The receiver1708may include any component or collection of components (e.g., down-converter, low noise amplifier, etc.) adapted to convert a carrier signal received over the network-side interface1702into a baseband signal. The signal processor1710may include any component or collection of components adapted to convert a baseband signal into a data signal suitable for communication over the device-side interface(s)1712, or vice-versa. The device-side interface(s)1712may include any component or collection of components adapted to communicate data-signals between the signal processor1710and components within the host device (e.g., the processing system1600, local area network (LAN) ports, etc.).

It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by a selecting unit/module, a RAN change unit/module, a determining unit/module, and/or a forwarding unit/module. The respective units/modules may be hardware, software, or a combination thereof. For instance, one or more of the units/modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).