Redirection and handover to voice over new radio (VoNR) layers

Solutions for providing a data traffic session include: while a voice over new radio (VoNR) capable user equipment (UE) is being served by a first cell that does not support VoNR, determining that a second cell that does support VoNR is available to serve the UE; transferring the UE to service by the second cell; and providing a VoNR call to the UE through the second cell. The transfer may comprise a redirection or a handover (based on whether the UE is already in a call). Some examples further include a trigger of: receiving a notification of an incoming voice call to the UE, receiving a notification of an outgoing voice call from the UE, and receiving a notification of a handover of a voice call for the UE.

BACKGROUND

Fifth generation cellular technology (5G) is often referred to as new radio (NR), whereas fourth generation cellular technology (4G) is often referred to as long term evolution (LTE). For 5G standalone (SA) implementations, voice calls may be provided as voice over NR (VoNR) calls. However, during the transition as 5G is built out in various cellular networks, not all 5G cells in a network may have VoNR enabled. Thus, at least some voice calls for VoNR-capable cellular devices (user equipment, or UEs) continue to be placed over 4G voice services—even when the VoNR-capable UE attempts to place a voice call from a 5G cell. The redirection from 5G to 4G voice (e.g., voice over LTE, or VoLTE) is referred to as voice over evolved packet system (EPS) fallback (VoEPSFB).

At some cellular sites, multiple layers (e.g., independent calls covering a common area) exist. For example, there may be a 5G cell that does not support VoNR operating at a first band providing a first layer, and a 5G cell that does support VoNR operating at a second band providing a second layer. A 5G UE within the common area may be being served by either one of the 5G cells. Unfortunately, when users who have invested in VoNR-capable UE are being served by a 5G cell that does not support VoNR, when there is an incoming call for the UE, the call may go to VoEPSFB, depriving the user of the benefit of a superior VoNR call experience.

SUMMARY

The following summary is provided to illustrate examples disclosed herein, but is not meant to limit all examples to any particular configuration or sequence of operations.

Solutions for providing a data traffic session include: while a voice over new radio (VoNR) capable user equipment (UE) is being served by a first cell that does not support VoNR, determining that a second cell that does support VoNR is available to serve the UE; transferring the UE to service by the second cell; and providing a VoNR call to the UE through the second cell. The transfer may comprise a redirection or a handover (based on whether the UE is already in a call). Some examples further include a trigger of: receiving a notification of an incoming voice call to the UE, receiving a notification of an outgoing voice call from the UE, and receiving a notification of a handover of a voice call for the UE.

Corresponding reference characters indicate corresponding parts throughout the drawings. References made throughout this disclosure relating to specific examples, are provided for illustrative purposes, and are not meant to limit all implementations or to be interpreted as excluding the existence of additional implementations that also incorporate the recited features.

DETAILED DESCRIPTION

Solutions for providing a data traffic session include: while a voice over new radio (VoNR) capable user equipment (UE) is being served by a first cell that does not support VoNR, determining that a second cell that does support VoNR is available to serve the UE; transferring the UE to service by the second cell; and providing a VoNR call to the UE through the second cell. The transfer may comprise a redirection or a handover (based on whether the UE is already in a call). Some examples further include a trigger of: receiving a notification of an incoming voice call to the UE, receiving a notification of an outgoing voice call from the UE, and receiving a notification of a handover of a voice call for the UE.

Aspects of the disclosure therefore improve the robustness, resilience, and reliability of wireless communications (specifically, voice calls) by steering voice calls to VoNR, for example, by transferring a UE from a first cell that does not support VoNR to a second cell that supports VoNR and is available to serve the UE. This improves user experience, due to the improved performance of VoNR calls compared with voice over long-term evolution (VoLTE) calls. Additionally, in some scenarios, non-voice data traffic sessions that occur in parallel with a voice call may provide superior performance when the UE is served by a 5G cell and the voice call is VoNR.

FIG.1illustrates an exemplary arrangement100that advantageously performs redirection and handover to VoNR layers (e.g., cells that support VoNR calls). A VoNR-capable UE102is in the vicinity of a gNodeB (gNB)110that provides a fifth generation cellular technology (5G) cell105v. Other cells (e.g., layers of service) are provided by co-located gNBs: a fourth generation cellular technology (4G) cell104and a 5G cell105a.4G is also referred to as long term evolution (LTE), and 5G is also referred to as new radio (NR). In the illustrated scenario, cell104supports only VoLTE, cell105adoes not support VoNR, and cell105vdoes support VoNR. In the position of UE102relative to gNB110, as shown, UE102may be served by any one of cells104,105a, and105v.

Thus, when UE102attempts to place a voice call, the voice call will be VoLTE if UE102is being served by cell104(due to UE102being backward-compatible with LTE), voice over evolved packet system (EPS) fallback (VoEPSFB) if UE102is being served by cell105a, and VoNR if UE102is being served by cell105v. VoEPSFB uses 4G voice infrastructure (VoLTE) for voice calls, and so may not perform as well as VoNR. This means that, without the redirection and handover to the VoNR layer (cell105v), the quality of the experience for the user of UE102may depend on whether UE102had been previously registered with cell105a, rather than cell105v. If UE102is not placing a voice call, and merely sending or receiving text messages, the service by cell105a(rather than by cell105v) does not impact the user of UE102. However, when UE102either attempts to place a voice call to another device (e.g., UE108), or there is an incoming voice call, gNB110redirects UE102to cell105vso that UE102may have a VoNR call106with UE108—at least up to internet protocol (IP) multimedia subsystem (IMS) access media gateway (IMS-AGW)124. (gNB110has no control over the voice call on the side of UE108.)

VoNR call106flows from gNB110as a packet data traffic session through a packet routing node120, and a proxy node122, to IMS-AGW124. An access node112and a session management node114provide management of data traffic sessions (including voice calls) for UE102. In 5G, access node112may be an access mobility function (AMF), session management node114may be a session management function (SMF), and packet routing node120may be a user plane function (UPF). In 4G, access node112may be a mobility management entity (MME), session management node114may be a system architecture evolution (SAE) gateway-control plane (SAEGW-C), and packet routing node120may be an SAE gateway-user plane (SAEGW-U). Proxy node122may be a proxy-call session control function (P-CSCF). Standalone (SA) NR is a 5G deployment that uses 5G for both signaling (management) and user plane traffic, whereas non-SA NR is 5G deployment that uses 5G for user plane traffic and 4G infrastructure for signaling. In the illustrated example, cell105vis an SA NR cell.

UE102provides UE capability information132in a UE Capability Information Indication message, which identifies the capability of UE102with respect to 4G, 5G, frequency bands, and VoNR capability, among other information. UE capability information132is stored in gNB110and/or access node112. UE102may be assigned to a specific cell by gNB110based, in part, on UE capability information132. For example, in addition to differences between 4G and 5G, different cells within 4G and 5G are distinguished by frequency and duplex mode. For example, an n41 5G band uses time-division duplexing (TDD) at 2500 megahertz (MHz), whereas an n71 5G band uses frequency-division duplexing (FDD) at 600 MHz. There are currently dozens of different bands among 4G and 5G, using various center frequencies, duplexing, and bandwidths.

A transfer control130at gNB110handles the transfer, whether redirection (while UE102is in idle mode) or handover (while UE102is in connected mode), of UE102to the VoNR layer (cell105v), so that UE may experience VoNR call106. Since gNB110may serve a large number of other UEs, load balancing134attempts to minimize the likelihood that one of the cells (layers) is overloaded, and can steer an incoming UE away from a heavily loaded cell. Thus, it is possible, that if cell105vis overloaded (e.g., already loaded above 70% when UE102moves unto the vicinity of gNB110), UE might not be redirected to cell105vand will instead have a VoEPSFB call on cell105a. Other load balancing measures may include splitting up a session of UE102across two different layers.

FIG.2illustrates a handover scenario200that may occur with examples of arrangement100. Specifically, scenario200illustrates a handover of UE102from gNB210, providing a cell205to gNB110providing cell105v. In scenario200, UE102is already in connected mode (e.g., a voice call is ongoing), and is moving away from gNB210toward gNB110. Transfer control130determines that gNB210is attempting to hand off UE102, and that UE102has an ongoing voice call as opposed to being in idle mode. Transfer control130also determines that UE102is VoNR-capable from UE capability information132.

Unless cell105vis overloaded (e.g., at or above 70% capability, or another threshold), UE102will be transferred to cell105v. If cell105vhad been overloaded, UE102was in idle mode, or UE102was not VoNR capable, UE102may have instead been transferred to cell104or105a. If cell205did not support VoNR, then UE102would be using 4G voice (VoLTE or VoEPSFB), and during the handover (transfer) to cell105v, the voice call is upgraded to VoNR.

FIG.3illustrates a flowchart300of exemplary operations associated with examples of arrangement100performing redirection and handover to voice over new radio (VoNR) layers. In some examples, at least a portion of flowchart300may each be performed using one or more computing devices500ofFIG.5. Flowchart300commences with monitoring NR SA cell105vsupported by gNB110, in operation302. Operation304identifies UE102in cell104,105a, or205(a first cell), which does not support VoNR. In some examples, the first cell comprises a 5G cell operating in a first band. In some examples, the first cell comprises a 4G cell.

UE capability information132is received by gNB110in operation306, which is stored in gNB110and/or access node112in operation308. A decision operation310determines whether UE102is VoNR-capable. If not, UE102will use 4G voice for any voice calls, as indicated in box312, and transfer to cell105vis not prioritized (e.g., UE102may be transferred to or continue to be served by cell105a). If, however, gNB110determines that UE102is VoNR-capable (in decision operation310), flowchart300splits into two branches.

An idle mode branch, comprising operations320-336, is followed if UE102is in idle mode, whereas a connected mode branch, comprising operations340-354, is followed if UE102is already in connected mode. The idle mode and connected mode branches are largely similar, although the idle mode branch has an operation for initiating a voice call (moving into connected mode and requesting a voice bearer) and the transfer comprises a redirection for the idle mode branch but a handover for the connected mode branch.

Following first the idle mode branch, decision operation320determines whether a trigger condition has occurred for determining whether a VoNR-enabled cell is available to serve UE102(e.g., whether a potential need exists to transfer UE102from cell104or105a). In some examples, the trigger may be receiving a notification of an incoming voice call to UE102and receiving a notification of an outgoing voice call from UE102. These may be a mobile termination (MT) or a mobile origination (MO) message, respectively. In some examples, gNB110determines the trigger. Absent a trigger condition, flowchart returns to operation302.

Otherwise, decision operation322determines whether cell105v(a VoNR-enabled cell, or a VoNR layer) is available to serve UE102. If cell105vis not available (e.g., due to overloading), UE102is not transferred and uses VoEPSFB, as indicated in box324. Flowchart then returns to operation302. Otherwise, decision operation322determines that cell105v(a second cell that does support VoNR) is available to serve UE102. This occurs while VoNR-capable UE102is being served by the first cell (cell104or105a) that does not support VoNR. In some examples, cell105vcomprises a 5G cell operating in a different band than the band in which cell105aoperates. In this idle mode branch of flowchart300, determining that the VoNR service is available to UE102is contemporaneous with UE102transitioning from idle mode to connected mode.

Decision operation326, which also occurs while UE102is being served by the first cell, determines whether a third cell that supports VoNR is available to serve UE102. In some scenarios, there may be multiple overlapping VoNR-enabled SA NR cells. If there are multiple overlapping VoNR-enabled SA NR cells, a load balancing determination is performed for those cells, in operation328. In operation330, one of the cells (e.g., cell105v) is selected, over the other VoNR-enabled SA NR cell(s) to serve UE102, based on at least the load balancing performed in operation328. If there had not been multiple overlapping VoNR-enabled SA NR cells, flowchart moves from decision operation326directly to operation332.

Operation332includes transferring UE102to service by cell105v. In some examples, the transfer comprises a redirection (e.g., operation332performs a redirection of UE102to selected 5G cell105v). In operation334, UE102transitions from idle mode into connected mode, and operation336initiates VoNR call106. Flowchart300then moves to operation360, which provides VoNR call106to UE102through the cell105v.

Turning now to the connected mode branch of flowchart300, decision operation340determines whether a trigger condition has occurred for determining whether a VoNR-enabled cell is available to serve UE102(e.g., whether a potential need exists to transfer UE102from cell205). In some examples, the trigger may be receiving a notification of an incoming handover of a voice call for UE102. In some examples, gNB110determines the trigger. Absent a trigger condition, flowchart returns to operation302.

Otherwise, decision operation342determines whether cell105vis available to serve UE102. If cell105vis not available (e.g., due to overloading), UE102is not transferred and uses VoEPSFB, as indicated in box344. Flowchart then returns to operation302. Otherwise, decision operation342determines that cell105vis available to serve UE102. This occurs while VoNR-capable UE102is being served by the first cell (cell205) that does not support VoNR. In this idle mode branch of flowchart300, determining that the VoNR service is available to UE102occurs while UE102is already in connected mode (e.g., UE102is connected with a VoEPSFB or VoLTE call).

Decision operation346, which also occurs while UE102is being served by the first cell, determines whether a third cell that supports VoNR is available to serve UE102. In some scenarios, there may be multiple overlapping VoNR-enabled SA NR cells. If there are multiple overlapping VoNR-enabled SA NR cells, a load balancing determination is performed for those cells, in operation348. In operation350, one of the cells (e.g., cell105v) is selected, over the other VoNR-enabled SA NR cell(s) to serve UE102, based on at least the load balancing performed in operation348. If there had not been multiple overlapping VoNR-enabled SA NR cells, flowchart moves from decision operation346directly to operation352.

Operation352includes transferring UE102to service by cell105v. In some examples, the transfer comprises a handover (e.g., operation352performs a handover of UE102to selected 5G cell105v). In operation354, the 4G voice call UE102had been experiencing in cell205is upgraded to a VoNR call (and is now VoNR call106). That is, in some examples, a VoEPSFB or VoLTE call through cell205is handed over as VoNR call106through cell105v. Flowchart300then moves to operation360, which provides VoNR call106to UE102through the cell105v, merging the idle mode and connected mode branches.

FIG.4illustrates a flowchart400of exemplary operations associated with examples of arrangement100performing redirection and handover to voice over new radio (VoNR) layers. In some examples, at least a portion of flowchart400may each be performed using one or more computing devices500ofFIG.5. Flowchart400commences with operation402, which includes, while a VoNR-capable UE is being served by a first cell that does not support VoNR, determining that a second cell that does support VoNR is available to serve the UE. Operation404includes transferring the UE to service by the second cell. Operation406includes providing a VoNR call to the UE through the second cell. In some examples, flowchart400commences upon a trigger, such as a mobile origination (MO) or a mobile termination (MT) of voice call service (e.g., an outgoing or incoming voice call, respectively), for which a voice bearer is requested for the UE, or a handover for an ongoing call.

FIG.5illustrates a block diagram of computing device500that may be used as a component of arrangement100, for example, as any component described herein that may require computational or storage capacity. Computing device500has at least a processor502and a memory504that holds program code510, data area520, and other logic and storage530. Memory504is any device allowing information, such as computer executable instructions and/or other data, to be stored and retrieved. For example, memory504may include one or more random access memory (RAM) modules, flash memory modules, hard disks, solid-state disks, persistent memory devices, and/or optical disks. Program code510comprises computer executable instructions and computer executable components including any instructions necessary to perform operations described herein. Data area520holds any data necessary to perform operations described herein. Memory504also includes other logic and storage530that performs or facilitates other functions disclosed herein or otherwise required of computing device500. An input/output (I/O) component540facilitates receiving input from users and other devices and generating displays for users and outputs for other devices. A network interface550permits communication over a network560with a remote node570, which may represent another implementation of computing device500.

ADDITIONAL EXAMPLES

An example method of providing a data traffic session comprises: while a VoNR-capable UE is being served by a first cell that does not support VoNR, determining that a second cell that does support VoNR is available to serve the UE; transferring the UE to service by the second cell; and providing a VoNR call to the UE through the second cell.

An example system for providing a data traffic session comprises: a processor; and a computer-readable medium storing instructions that are operative upon execution by the processor to: while a VoNR-capable UE is being served by a first cell that does not support VoNR, determine that a second cell that does support VoNR is available to serve the UE; transfer the UE to service by the second cell; and provide a VoNR call to the UE through the second cell.

One or more example computer storage devices has computer-executable instructions stored thereon, which, upon execution by a computer, cause the computer to perform operations comprising: while a VoNR-capable UE is being served by a first cell that does not support VoNR, determining that a second cell that does support VoNR is available to serve the UE; transferring the UE to service by the second cell; and providing a VoNR call to the UE through the second cell.

Alternatively, or in addition to the other examples described herein, examples include any combination of the following:determining that the second cell is available to serve the UE is contemporaneous with the UE transitioning from idle mode to connected mode;the transfer comprises a redirection;determining that the second cell is available to serve the UE occurs while the UE is already in connected mode;the transfer comprises a handover;while the UE is being served by the first cell, determining that a third cell that does support VoNR is available to serve the UE;based on at least load balancing, selecting the second cell to serve the UE over the third cell;the first cell comprises a 5G cell operating in a first band;the second cell comprises a 5G cell operating in a second band different than the first band;the first cell comprises a 4G cell;the second cell comprises a 5G cell;triggering the determining that the second cell is available to serve the UE on at least one trigger;the trigger is selected from the list consisting of: receiving a notification of an incoming voice call to the UE, receiving a notification of an outgoing voice call from the UE, and receiving a notification of a handover of a voice call for the UE;a gNB provides the second cell;determining that the UE is VoNR-capable;the gNB determines the trigger;the gNB determines that the UE is VoNR-capable;the gNB selects the second cell over the third cell;while the UE is being served by the first cell, the UE is connected with a VoEPSFB call;the VoEPSFB call through the first cell is handed over as the VoNR call through the second cell;while the UE is being served by the first cell, the UE is connected with a VoLTE call; andthe VoLTE call through the first cell is handed over as the VoNR call through the second cell;

The order of execution or performance of the operations in examples of the disclosure illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and examples of the disclosure may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the disclosure. It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. When introducing elements of aspects of the disclosure or the examples thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. The term “exemplary” is intended to mean “an example of.”